Hi Gruhs,
Many thanks for your very comprehensive reply.
In view of the fact that the battery is soldered, I have decided to leave it and just reload my PROGRAMS and REGISTRATIONS from floppy every time I switch on.
The people who took the place of Radio Shack in the UK is Maplins, a very good store and quite close by my home so I could probably source the battery ok but my soldering skills in general are crap so it's better left alone.
As I use the MS40 mainly just for strings (still far better than the offerings of Technics KN7000 & Tyros4), I just need my Programs & Registrations in place so I will manage for now and consider buying a Midjpro.
Thanks again for your help.
Tony