W715 Assisted GPS

Ok here's the story, last week got a warranty replacement W715 courtesy of Vodafone UK. The previous handset LCD had started to leak crystal but was otherwise 100% functional and I made good use of the GPS. The replacement they have sent me just will not be assisted by the SUPL server though? GPS works on standalone mode but takes forever to get a fix. My internet settings are fine and I can browse the web, the world icon even flashes a couple of times when opening 'Status info' but the satellites do not all appear in the circle within 5 seconds as they used too... Rang Vodafone and they said no problems in the area and they don't really understand the problem anyway prefering to blame SE... As i'm a good customer they sent me another replacement which has EXACTLY the same problem. The only difference between these handsets was my first being a CID52 and the latter two being CID53. I have now debranded the 2nd with generic Nordic firmware (i'd done this with my original phone as well) and still no joy. It appears to me that the SUPL server cannot be reached but there appears to be no way of updating this on these phones? Where do the SE's look to find which AGPS server to use? If it's hardcoded into the firmware and the server has gone down/changed address surely many people must be noticing the lack of assistance GPS! Thanks in advance.