KiwiKarl:
I can't offer you a magic wand to force 'Fifteen 02' or indeed Virgin (or MBNA).
However what you need to do is (what you have done) give and document 'Fifteen 02' one opportunity to remedy the issue and failing that give Virgin (or MBNA) one opportunity to remedy the issue, then failing that invoke the formal Virgin (or MBNA) complaints procedure.
Its a fairly accelerated procedure initially. Ask the adviser, if you don't agree ask for a manager and if you still don't agree contact in writing the address stated in the complaints procedure. If you remain disastisfied after 8 weeks regardless of further progress, ask the Financial Ombudsman Service to accept the complaint.
I cannot promise an outcome in you favour, and it certainly won't be quick, could be up to a year, but it's free to you and costs MBNA a hefty case fee regardless of outcome. If that doesn't focus Virgin (or MBNA) then nothing will.
That's it. Get on with it!