I am not very hopeful. Sorry.
Have you tried restoring your oldest *.mbf file -- one that predates the problem? How about your old computer... could the *mny or *.mbf still be there? It may be two years old, but that seems better than starting over with a fresh file.
There is one thing I have suggested in the past, but nobody ever reported that it worked to solve a problem. But here it is:
In case the sunset salv.exe is improved since the Money 2005 version, it may work. Yet nobody has ever reported joy after trying. This is a long shot, and you could be the first. You can find links at
https://microsoftmoneyoffline.wordpress.com/2010/05/09/intro/#downloads which is on MICROSOFT MONEY OFFLINE -- Ameridan's Blog
Download the Money Plus Deluxe Sunset install file into a temporary folder. Use 7-zip, WinRar, or other zip program to extract the contents. I think that file is a self-extracting zip file of some sort, and I just tried it with 7-zip. The only file you are looking for is salv.exe.
Run salv.exe file. It will look the same as when you do your standard file repair with Money 2005. Put the result in a new file, maybe called hope2023.mny. See if that works. If not, I don't know that there is any hope, unless you find a *.mny or *.mbf file that predates the problem.
The Money Plus Sunset salv.exe will work with your UK Money 2005 file, but Money Plus Sunset itself will not work with your UK money file.