Per Regulation14(b) of SI 1994/1811, HMRC may be represented by
a barrister, advocate, solicitor or any officer of Revenue &
Customs.
You should advise the appellant (or his agent) before the
meeting who will attend on behalf of HMRC.
You should also advise the Commissioners Clerk no later than
the day before the hearing who is attending for each side including
the names of any observers.