Sources I have used are almost always the typical UK vendors: lordgun, probikekit (all over) and most recently Merlin cycles which I just saw has some Veloflex and Vittorias in stock in the 50-60 buck range. Most are models phasing out which you will note if you watch things. I bought all my vlaanderens at good prices because they were moving them out. On a tip from this board I bought 5 more after not being able to find them anywhere for a while. I would not hesitate to buy their newer models.
this thread needs more pic and more of your alpina . Love the color. Below is my Bruce Gordon with pretty sure vlaanderens.