Believe it or not I think I have sorted it
With your help and measuring the continuity I started to think what else is preventing it from firing up - esp when it worked with the jumper lead between ale and Ls
As I don’t have a physical timer clock on the boiler but a wireless receiver I had a ‘ BINGO” Moment - What if I disconnected this and did it interfere with the Lyric?
Receiver removed and is working fine now
Just need to obtain a blanking plate
Many many thanks for you invaluable help mate 🤝