Just acquired my 2011 sd4 Hse , when I switch on the engine on all the lights go out but it beeps a single beep for aa few seconds is this normal?

It's likely an issue with the PDC. Does the indicator in the PDC switch also blink? Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

What is the pdc

Parking sensors indicating a fault, top of the centre console is the switch for it, stick it in reverse and it'll flash indicating a fault

I will try that, if it is faulty, is a local auto electrician capable of fixing it or do I need to take it to a Land Rover garage.

try cleaning them,mine used to do that when wet or dirty.