Giggey - OK, as I understand it, you have a Spanish issued JAA CPL(A) with an A320 type rating (endorsed as co-pilot only) and, presumably, an IR with ATPL theory credits and you wish to change your State of Licence Issue to the UK.
There is no problem with your licence - if you meet the residency requirements of JAR-FCL 1.070, the CAA should be content to take that on, along with the IR and any other ratings. The problem is with the A320 type rating because the UK do not issue or recognise a 'co-pilot' restriction. Everyone undertaking a MPA type rating at a UK approved TRTO will do so as PIC and will be issued with an unrestricted type rating.
All that I can suggest is that you offer to undertake an LST at a UK approved TRTO acting as PIC, which should allow the Authority to issue an unrestricted type rating. However, the final decision rests solely with the UK CAA and you have to realise that there is no longer anybody in that organisation with the experience to properly understand your problem or to agree a pragmatic solution.