XJ600noob

Hello everybody my name is Arnar I live in Iceland and a few months ago i bought my first bike, my choice was a cheap old pre division xj600, it had been sitting in storage the last 6 years or so and was missing a few pieces also the carbs are stuck and all around the bike is not in a very good condition, as i have quite a few American cars jeeps and such which require quite a lot of maintenance I have skills suited to rebuilding for instance an old bike or old cars and such. Funny thing is i have been calling the only licensed yamaha dealer here in Iceland and find them very pricey, for example for the price of two new engine heads (not that i need two) i could buy a brand new xj6. We are not a big nation just a little more than 300 thousand people and due to the size of the country and how many bikers there are in Iceland there are no used bike parts dealers here (the business is not that much a person can live only on dealing in used bike parts)anyway going through ebay and the parts dealers i have found on the internet there are parts that i can not find for example new main bearings camshafts and other bits and pieces some parts i could find used but then again when rebuilding a bike some parts must be bought new, and with the prices at the only dealer in new yamaha parts in Iceland it would probably be cheaper for me to fly to London buy the parts there and take them back to Iceland myself in my luggage. And here is the question can you recommend to me some parts dealers in or near London who would possibly have those parts i need on stock and maybe some used parts dealers who could have used parts for my bike, it is a 51j registration xj 600 made in 1987. With thanks Arnar Helgi Oskarsson.