Anyone any idea what one of these is worth?

From the bits of info I can find on google, most of them seem to be from the late 50's and Reynolds 531. This one has Vitus tubing and is said to be mid 60's.

Stonglight triple cottered chainset, Simplex 15 speed gears, the wheels have been replaced and possibly the saddle. The rest seems original although it all needs a good clean.