Thank you for that. I do not believe it's the battery. There is only a single click when turning the key. But tomorrow I will try it with jump leads attached, just to rule that possibility out. When I was getting the relay click, I was also getting three beeps. But all the other electrics were working fine. With headlamps on, and hazard lights on, the wiper motor was going okay - usually a sign of a pretty healthy battery. But starter motor was still not even engaging. Strangely enough, got the car towed back to my house today from the garage, and whilst it was being towed, put it into second gear to see if it would start, and it started without hesitation. But will not even attempt it with the key??

Naeem, July 2016

Thanks, but now I am be getting out of my comfort zone. Going to google where starter solenoid contacts are, and what follows. Seems it should be a really simple fix, but garage failed me.
Bought another car yesterday, as was giving up on this, but it seemed so lively and responsive when it started during tow this evening. Much better than the 'replacement' car I bought. I would much prefer the berlingo to be alive again!. It's so much faster, more economical, more load space etc etc.

Naeem, July 2016

Think it through. Power goes from battery to vehicle OK, as evidenced by the lights etc.

Power goes from battery to starter solenoid coil OK, as evidenced by the click.

Does power get to solenoid CONTACTS?

Does power get from solenoid contacts to the starter motor itself?

Are the solenoid contacts OK?

Is the starter motor OK?

Are ALL the high-current connections OK? - And that includes the earth strap between the angine clock and the chassis / battery negative

XXX, July 2016