it was all dd1's work, not mine 
re: mouse - have a look at Inclusive Technology. if anyone has a suitable mouse, they will (maybe google afterwards for brands/makes to get it cheapest?). I use an Apple magic mouse at home - it is a click anywhere mouse, so dd1 gets on ok with it, but not sure how well it woudl work with a PC (I htink functionality is not great). along the same lines, they ahve their touchpad (instead of a mouse) - I don't have one, but I imagine compatibility issues would be the same as for the mouse.
otherwise, dd1's school have put a sticker on the left click button for the mouse, and she gets on ok with that (after a fashion)
software wise: at dd1's school, they use education city. it is subscription, though. I don't think the american accent is a huge problem (dd1 has loads of american apps on her ipad, but hasn't suffered fromthis).
alphablocks always used ot be available on the cbeebies webiste/iplayer - haven't looked for a while, though.
what about CD ROMs? I was looking around a while back, and found some - will try to find them again, hang on..... things like this (or similar) - I haven't used any of them, as most of them not Mac compatible... there are loads of different ones out there for Windows. I bought dd1 a couple of the Dora games, more for practising mouse control than the educational aspects, but they do have some bits which are numbers/letters focussed.
good luck!