lol! Really ? I wouldn't of thought the fuel sending unit controls how much you put in the tank ? When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car

I used the majority of the fuel and filled up with 45 litres but the handbook says it should take 68 litres. The tank would not take anymore.

When the garage explained what they were doing they said that the tank is split into two - it overhangs on each side of the propshaft?? (maybe - can't remember) so wondering if somehow the fuel is not filling up on the other side??? Or if they have put a smaller one of to save money??

The single tank is a saddle design, so it fills one side first and then spills over to fill the other side.
When using fuel there is a small pump that transfers the fuel from the "overspill" side back to the active side.

So there are ttwo gauges that read completely different levels, the ECU then calculates the remaining fuel from these two readings. It is possible to have one side empty and the other side half full, the instrument readout would read quater full.

When fitting the two new tank gauges, it is quite difficult (complete ), it is very easy to bend one arm, or fail to clip the guide rail in properly between the tanks. Either would give a faulty reading. Looks like the garage need to do the job a second time, this time taking more care.

I would suspect one gauge is reading low, so the instrument panel will indicate no fuel left, even with 20 litres remaining. The real bug bear is that the car thinks there is no fuel left so it cuts the engine so that you do not physically run out of fuel and require a manual system bleed. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

Thanks for your reply Andy.

Car is now back in the garage after breaking down on me! A sudden reduce engine management warning flashed up, the car chugged and spluttered and then died!!!

RAC machine read low fuel pressure but also high fuel pressure just to confuse the issue??

Waiting for the garage to get back in touch but any ideas / advice would be greatly appreciated

Hopefully you have run out of fuel
The gauge can read half a tank, and still be empty, this would give the low fuel pressure reading, and give a reduced performance waring - briefly. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

Apparently, it is something to do with the fuel pump (I think he said). Something about air is getting into it? Seems to be charging a lot at £135?? Does this sound right?

The fuel pump is at the wrong end of the fuel line.
"normal" systems have the fuel pump in the tank, so the fuel line is pressurised - if you have a leak then fuel squirts out - not good if it's petrol. This rarely happens, but they do sometimes weep - still expensive if you look at the price of fuel.
The FL2 system has the fuel pump at the engine end, so it has to suck the fuel under vacuum from the tank, through the fuel filter and up to the engine. If you get a leak then it will pull lightweight air through the leak rather than heavy fuel from the tank.

You have to remember that it takes a relatively large hole to pass fuel through, but a tiny hole to leak air in.

Obvious places for an air leak are the unions, at the top of the tank (lift up rear seat, big rubber bung under carpet), at the fuel filter unions, at the fuel pump itself.

£135 is an hour, to an hour and a half, reasonable time to ceck all the unions, find the faulty one and attempt a repair, then bleed the system. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

Grrr - I am sick to death of this fuel tank sender unit!!!

Garage have just rang to tell me that when they replace the fuel tank sender unit they only replaced one of them (apparently there is 2) and that is why my tank will only accept 45 litres instead of 68 as the second tank is nearly full of diesel but the pump is not sending it through!! More expense.

Luckily they say it is a learning curve for them so they are willing to stand the labour charge so I will only have to pay £68 + VAT for the part but this ontop of the fuel filter head comes to £218. Must be nearly £1,000 now to get this problem sorted (and it better had be!!! ).

Could be worse, you could be feezing your off crawling around on a frozen garage floor doing the job a second time yourself.
Local LR dealer quoted £800 +VAT - so just short of £1k to change both fuel senders, they would not change one on it's own.
One of the best bits is trying to empty the fuel prior to dropping the tank - you do have somewhere spotlessly clean to put 60 litres of fuel don't you? Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

looks like im a joined up and subscribed member of the Dodgy Fuel Sender Club

going from half way between a half and quarter tank to zero and then back again and down again

got a 200mile trip to do on Saturday too  Former Mod/Member, with the most post & Chicken George Arch nemesis

Ooh, could tip the balance on what car to get next, sooner rather than later.

quite possibly if warranty doesn't cover it especially at the £800 cost to replace the fuel senders is correct Former Mod/Member, with the most post & Chicken George Arch nemesis

wow, and for that money you won't feel a better ride or go faster or think it's quieter.

Just an important needle on the dash

EDIT: So I suppose the 'range' reading is all over the place also

the range starts dropping as soon as the needle takes a dive, all the way to zero, then as soon as the needle bounces back it starts to slowly rise again, and visa versa Former Mod/Member, with the most post & Chicken George Arch nemesis

Well at best it could be a plug/socket come loose, here's hoping