Peugeot 205 Diesel starting problems, engine not turning over sometimes?

Hi,

I have a 1995 Peugeot 205 1.8TD Mardi Gras which has an intermittent starting fault. Sometimes, when turning the starter switch the engine will not turn over, each time all I hear is a click coming from the fuse board and nothing else. It is not the starter solenoid or motor because they have been changed recently and the fault occured on all combinations of old and new parts.

I see a number of relays on the fuse board. Is one of these part of the starting circuit?

It was in for some bodywork repairs recently and the garage told me it's probably the starter switch. Obviosly I don't want to spend £60 on a new one only to find out it's a relay at fault. I have tried being quite forceful with the key but it doesn't make much difference.

As I say, this is an intermittent fault. It's left me stranded for an hour or so a few times then it suddenly works again. This has happened in hot and cold weather.

I've also checked the earth to the engine which looks good. The battery is also fine.

Any help will be appreciated,

Thanks, Steve (UK)