Hi Barney
Good news that it would appear your friends tumour is superficial, I'm sure the Southend doctors are doing the best thing regarding treatment.
From our experience, your friend can either self-refer to the Royal Marsden (just check out the Marsden website on how to do this) or ask for a GP referral. This is the way we did it, we weren't totally happy with the local response so I did some research on the Marsden and found the leading consultant and asked my mums GP to do a private referral. Private referrals are expensive (£350) but you can also ask to be seen on the NHS.
The Royal Marsden is the leading cancer hospital in the UK, so you can't go wrong going there, even if it is to double check what the Southend doctors are doing.
My mum is about to start her 4th chemo, its been tough, but we have recent CT results which suggest the treatment is working.
Best wishes
Moglie