Hot start issue, coil light stays on (solid light)

[Josie30]

I have an A3 2.0 TDI. For quite a while now I've had trouble with it starting which seems to have got worse over time. Realised coil light would not go off hence the not starting and then as the weather has got warmer have noticed that is when it does it. This would explain it doing it alot more now. 

Garage put it on diagnostics and relay came up which they've changed. They have now told me they've done all they can and they think it is a wiring issue. Since mot I've spent £400 and dont want to put alot more into it as need a new car anyway. 

Just thought I'd see if anyone has any advice incase it could possibly be a simple/cheap fix to help tide me over with my current car until I get a new one.

My Dad and I have also changed air purifier & fuel filter.

Appreciate any help 🙏😊