I hope they don't change the page address in the future, but if they do, here is a screen grab of the page.
I gather that Robin Curtis (a key speaker at EcoBuild 2011's seminar on GSHPs) closed his UK company Earth Energy and has joined up with NeoEnergy, and later with Mimer, also a Swedish company.
NeoEnergy also sell software called Earth Energy Designer (EED) for borehole heat exchanger design, and they provide other specialist testing and prediction services (click on Service List on their main site)
Their links page has no active links to any UK sites, which seems to be a pity. I will write to them.