I can report that the dangle and SIM that I bought worked perfectly. Just one or two odd places where it would not pick up a signal,strangely,one was a supermarket carpark,but even in remote central Spain I could manage my sharedealing account!

Turns out that my Algarve apartment is equipped with wi-fi,so it was only at busy times that the dangle was needed once 'on site'.

Again,thanks for your help.