Devon Discoveries?

Do they exist? I've spent a couple of weeks scouring Autotrader and snotbay to no real joy. I'm looking for a 300TDi Auto and there are none! Go North of Manchester and they can't give them away! The problem I have is I'd be nothing short of an idiot to buy on spec so I think I'll be waiting a while longer. Is it a realistic consideration to convert a manual to auto? I've priced it up (roughly) and it looks like it'd not cost more than a few hundred quid in bits. Reckon I'm missing something here though?

Would I have to have the vehicle inspected at all as it would have to be changed at DVLA. Would that then mean it is a modified vehicle and cost me a mint in insurance?

I can't bring myself to buy a ****gun, as they are just ****.