When you say you have noticed your proxy going from 1-7 what do you mean?
have you been testing it on different sites? if so, reporting different proxy servers is not unusual, as you will be served by a range of proxies, as different proxies cache different sites.
Have you tried specifying a proxy that is outside of the luton range? Bristol 2 is 62.255.0.5 and cardiff 2 is 62.252.32.4 so you could give one of those a try
