FartPower,
I went to the one in March and it was an interesting day. You get a debrief afterwards with a volenteer pilot of the Guild.
Worth £150? Not much to spend when you consider the amounts you are looking at for a CPL is it? Having said that, never be put off your dream by a poor result - as the Guild say themselves, it is only an indication and nobody will find out what you scored when it comes to job hunting after training.
If you want anymore info then just drop me an e-mail.
All the best, VFE.