Found a thin, small nail (looks like the sort you can hang small picture frames with) stuck in the tyre today. The top of the nail lays flush with the top of the tyre tread but is located in the gap between the treads. in the centre Have no idea how deep it is or how long it may have been there. Nail didn't move when tried to wiggle it. Anyone had a similar experience or suggestions welcome to a course of action. Would LR Assist be an option? or is it down to the nearest tyre repair shop? I have a full size spare.

Radial tyres will self-seal round a nail (when they first came in, manufacturers stopped fitting spares!). It is safe to drive if you check the pressure. That said, get it repaired by a competent tyre man asap. Make sure it's rebalanced when he refits it.
Don't pull it out, as that will deflate the tyre.

Those little pins vary from 20-30mm so there's no saying if it has or has not pierced the inner wall of the tyre.
If a tyre fitter pulls the nail without loss of air I'd imagine he'd prefer to drill and plug it for safety.
If you are going to pull the pin then I suggest you find a shelter, sorry put a dab of tippex or road marker to ensure the problem area can be located easily.
Regarding assistance, I wouldn't know bud.

Get a cup of water, put a small squirt of Fairy liquid in it and stir it up, pour it over the pin and wiggle it. If it starts to show a froth, it's gone through. If not, pull it out and check it again. You can always push the pin back in to get you to a tyre shop. It can only be repaired if it's in the central 3/4 of the tread. Make sure it's a proper mushroom patch that's used and fitted from the inside of the tyre. Do not under any circumstances allow them to repair it with the string repair stuff. Past: FL2 TD4 HSE Auto
Evoque SD4 Dynamic Lux Auto
Present: Audi A3 S Line.

Hi , Steve D is right on the button.
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I would always select the smaller private guy tyre fitters where you can stand close to the guy and know what he's actually doing to your tyre and rim, some of the larger units keep you in the lounge with a cofee and you've no idea what the possible underpaid undertrained school leaved has done.
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When its your bum on the seat at 70mph its important.
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I think the Mushroom maybe a legal requirement however I know that straight rubber plugs are still in use.
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All the best luck with the repair and kind regards from Fred.
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Thanks guy's, I shall be up early for a Sat morning repair job. Will report back when done.

One other thing - when the repairer refits the tyre he should check the wheelnuts with a torque wrench. My new local man (I have just moved house) did not do this, and when I checked them myself they were not tight enough. They should also be rechecked after 25 miles. If you don't have one, it's worth getting a torque wrench from Halfords or similar for just this purpose.

Had a screw nail in tyre approx 1/3 way in and took to Kwik-Fit who insisted I needed to buy a new tyre. Thought quote was too expensive so took it to local garage recommended via www.blackcircles.com which was much cheaper and on driving in noticed several Land Rovers (turned out to be the owners cars!). Mechanic examined all my tyres and said all I needed was puncture repaired for £12. All sorted now and very happy again!! Not ever going back in to Kwik-Fit again!