UK prices are subject to 50% guess work & 50% ebay market forces.

So as a holder of of 2,317 UK chips... here's my stab

Rendezous 5UKP
First Issue Scroll Mold 1982 (R4)
In the range $10 - $25

Martell 5UKP
Only Issue (R6)
In the range $6 - $15

Royale Chimes 50p
2nd Issue Brown/Orange Scroll (R4)
In the range $5 - $10

Rendezous commands a higher price as a London Chip (premium)

A royale Chimes 50p sold on ebay in March for $6.51

But as always... should two or more collectors go for any of them in a big way the price could zip up.