Update:
Bought new sender - very reasonable £62
Finally got around to fitting it today, gap set to 1mm, set off on test drive in eager anticipation and...................nothing, not a sausage
Back to garage, scratch head, jack up car, remove wheel, scratch head again.
I opened up the gap to 2mm, put it all back together and it all works perfectly
Very happy me!
Thanks for all the pointers guys, got there in the end 😶🌫️
Edited by - Garry7 on 15 Apr 2014 18:36:02