I am planning to apply for a phd that is based at collingdale and wanted to check that since its inside the M25 it would count as the london stipend. Also do we get taxed as phd students or not?
Thanks!!

Not sure about the London boundary. But you don't get taxed on your stipend. You do get taxed on any earnings outside of the stipend, but only after you have earnt over about £5k.