i Have just looked at the 2007 lasors, section A8 (on the CAA website) and it says the following
An applicant who has a valid pass in JAR-FCL
Theoretical Knowledge Examinations completed
through a UK Approved Training provider, wishing to
complete a CPL modular course of flying training in
another JAA Member State should in the first instance
contact the Authority of that Member State. The
applicant should confirm with that other State that they
are willing to recognise their JAR-FCL Theoretical
Knowledge Examinations and that they will be the
‘State of Licence Issue’.
It also lists that to transfer the license to UK some forms need to be filled out, and that you need to be a UK resident for more than 185 days a year or be employed in UK.
So it looks like it is possible.