Hi Mike. Maybe I can help.
Cappos were never officially brought into Australia (that's where I am!) and finding parts for my one are even more dire than in dear old Blighty!
But there is some good news! I managed to get a contact name in Japan who sources hard-to-find [Japanese] car parts there. He is Jesse Streeter (http://www.jessestreeter.com
), an Aussie who has set up shop in Japan specifically for this purpose. I got a few items from him in the past and he's very reliable! All you need to do is to send him the part numbers and he'll get back to you in a few days time with their availability. (I only use him for parts which the main dealers here can't supply.) All parts are priced in Japanese Yen (JPY): Jesse deals only with all Japanese marques; so you'll have to let him know what car it's for when enquiring.
I usually pay [for my parts] by cash over the counter at a branch of his bank because he has an Aussie bank account; but I'm not too sure how this can be done from the UK....maybe an on-line cash transfer by internet banking?
His method is very simple: there are 2 payments to be made... one for the parts and another for the shipping by courier. How Jesse does it is to order up all the parts required by his customers [as a bulk delivery to his premises] in the course of the week; and then he packages up each order individually for each specific customer, ready for despatch. The first payment is to pay the parts suppliers separately; and the second (a few days later), shipping by courier to the customer. OK, it's a little messy trying to describe it in words; but this method works just fine!
If you ordered up bulky items such as the front bumper or body panels, I suggest having them delivered straight to the body repairers instead of to your home address. (That'll save you loading up your car and taking them there yourself; unless, of course, you really want to .... )
Hope this helps.