It has been stated on numerous occasions, why not simply remove the 61.75 restriction and get yourself a totally unrestricted FAA certificate.
For folk who have a single requirement for example a one off vacation trip to the US - then a 61.75 is fine but if you intend to actually use it on a more frequent basis - then it is difficult to be sympathetic for you having jump through ongoing hoops and paying the CAA fee over again.
Also remember you will have to do it all again when the FAA photo certs come into effect.
Bite the bullet and separate your nationally issued license from the FAA certificate and be done with it.