hi, thanks so much for you replies. i have tried a couple of those leads but need to follow up again. Yes, maybe fabrication will be the way forward. I was hoping to find one gathering dust in a shed somewhere - as i just found one 5miles from where i live, and he sold it 2 weeks ago - what are the chances?!
MP - the same happened to mine, i'd taken the engine apart to service and paint, and the manifold spent too long on my bench. When i went to reassemble there is a deep crack going right through it... Thanks again for your help, please keep your ears to the ground and if anything else comes to you let me know. Cheers, Rich