Any ideas which visa would be best as there are to many im thinking ov moving to udon area with thai wife from uk.im 58 so there is a retirment visa or marrage visa .what would be the easyest for me i can easy meet the 800 thb thankyou

It is your choice. The extension of stay (it is not a visa) based upon retirement requires less paperwork than one based upon marriage .but requires a lot more financial proof.

The extension of stay based upon marriage requires 400k baht in the bank for 2 months or proof of 40k baht income versus the 800k baht in the bank or 65k baht income for retirement.

First you would need to obtain a non immigrant 'O' visa for being married to a Thai National, a single entry is available for London Thai embassy either by post or in person,  and consulates in person, but may have to be pre approved see your local consulate for details. multi entry is only available from London, 

 

once you have the visa then follow Ubon's advice above