Right! Am in organised mood so just called them. We have to pay up front in full, so £83 for spa access or one of the following special deals which are available on the 5th:
109 - spa, 25min treatment
130 - spa, 50min
150 - spa, 80min
afternoon drink and dessert
I'm going to go for the basic package as I don't want the drink or dessert (!) and I know from going there previously that you can always book treatments separately on the day if you want to. You only get a group discount if you are a party of 10 or more.
On a different note, I have just spooked myself a bit, realising this is an open forum and we may have cyber-stalkers! (call me Paranoid). Anyway - perhaps we should pick a different day for this spa outing, and discuss it offline in PM messages?