I looking at a cat 312c excavator after resourcing the serial number cat told it's a machine from the uk , should I pass it up I just don't what to do
It depends on the particular Cat dealer. You need to call them back and ask them two things, 1) can you look up and supply parts for it, and 2) can you provide service for it. My Cat dealer won't touch them. Many moons ago I asked them about a part for a 307SSR, they replied they can't look up parts for it. So I asked the service manager what they do if a customer brings one in for service, he replied he tells them they don't work on those machines. On the other hand, I know of a Cat dealer in Washington State that will work on and provide parts for pretty much any Cat grey machine. Call your local dealer back and ask those two questions, that should help you decide what to do.
Post the Serial Number here if you have it. A simple check will reveal if parts and service information is readily available.
Dbn-00752
I worked for the CAT dealer in Portland, Oregon and we had a common sense approach, we urged people that owned grey market CAT equipment, usually from Japan, to buy a parts book from us, and the policy at the time was to order two, one to sell to the customer and one for the "Grey market shelf". The parts descriptions were in Japanese, but it was a rare thing indeed that the part wasn't also used in a US made machine. A sale is a sale, and service is service, we never turned anyone with money away, LOL. Worked for a contractor that had a D6D made in the UK, never had any issues with it, or getting parts, functional equivalent.
As far as I can see from a quick scan all parts and service (systems operation, test & adjust, troubleshooting, etc) information for that particular machine is readily available on-line. I personally can't see any reason for your local dealer (Yancey..?) not to support the machine but you would be better getting confirmation from them.