Obviously, Swift should be your 1 st port of call. You never know they may have some in the back locker somewhere.
You have mentioned replacing them with those from a newer model, but the problem could be trying to get all the old ones off without ruining the paintwork. A professional with a good steamer may be the answer there. The next point is that if the new ones are not the same shape and size, you will probably see the outline of the old ones in the paintwork.
The last option I could suggest is to take pictures and maybe get new copies made by a printer.