Have I purchased your father's car? 😁 ... Thanks for all your help and advice, it's in the garage now, I've sent them all the info from here and hopefully they'll sort this, and the smokiness/lumpy idle too.

I noticed after I got it back from them last time that the radiator fan seemed to always be running flat out, heard it winding down every time I shut off the engine. Wasn't doing it before it went into the garage!?? One thing at a time though. I'll report back and let you know how I get on.