finally…..
the issue was with BT. when we signed on, they gave us a username and password. they then followed this up with a different username and password, so we had 2 acccounts doh!
when we tried to log on, the orginal account wouldn't log on so we tried the 2nd account and it worked.
we then asked for a static ip which they said was working etc. but we couldn't get it to route etc.
so after hours on the phone and getting up to top level support, turns out that we shouldn't have been able to use the 2nd account. in fact, they couldn't believe we were actually logged on using an account that shouldn't be in use.
so we then logged on with the original account (which we couldn't do originally) and bang.... static ip's are now matched etc.
BT........ !!!!!