If I read the regulations regarding the engine hours correctly; the limitation that is mentioned here only applies if you want to put the aircraft on PT CofA; not if you go for the Pvt Cat.
I was quoted about 500 pounds for the conversion onto the G if all is well, plus any remedial work needed to satisfy the surveyor of the CAA.
There is a difference in standards between what is acceptable to some local non UK outfits and the CAA Surveyors.
As per always; Caveat Emptor.
There is obviously the option of operating the machine on the current registration although this does have some limitations. Getting the annual may involve a trip once a year to its home grounds and overflying other states with a licence from someone other than the registered aircrafts one is potentially difficult.
HTH
FD