That's pretty much my area too, I agree the cupboard is just about bare. I usually resort to travelling up the A3 to Surbiton, Kingston etc. The problem is that adds 1-2 hours to the time, so covering is more difficult, hence punts are less frequent. Alternatively there's occasionally a touring girl turns up in the area, but that's not very often. Slough, Maidenhead and Heathrow is another option with the same limitations. I have tried Reading once or twice, but I find it difficult to sort the wheat from the chaff there!
I've tried contacting a couple of Academy girls, but never had a reply. I've given them up as a bad job, and if I find a girl listed as Academy, I move on.
Back in the Cloud9 days there were usually some good pickings in Guildford. Then Guildford Gems lowered the standard, but still had the occasional, well, gem. Now they've merged, changed, moved, whatever, and Surrey Gems service and charges are shite - I haven't used them for about 2 years.
To answer your last question, I don't think you've overlooked any hidden diamonds
Perhaps we should start a campaign to get some WGs to move and set up in the area. Perhaps the local council could offer a grant