Tom I've only just read your message.
But I decided I
had to learn avrdude, so I installed it and eventually got the USBasp programmer to program the board via the 6-pin ISP with this command:
avrdude -c usbasp -u -U flash:w:stk500boot_V2_mega250.hex
There seems to be no need for fuse settings as avrdude works in "safe mode" by default. I think it sets default xtal fuse settings, but I'm not 100% sure.
Zadig 2.3 is an excellent signed driver for USBasp drivers and more. I installed libusb-win32 (v 1.2.6.0) which is an open source USB driver library, which mounted the USBasp programmer as a USB device. Its a cheap programmer, under £5, a Chinese clone of the original design (I think) by Thomas Fischl:
http://www.fischl.de/usbasp/Then I could run your Install Utility, but Java seemed to hang after firmware upload so I killed the install. Then started install to read the EEprom which was empty, I programmed the EQ5-belt config and the data uploaded ok.
Yes the long way round, but I learnt a lot and feel quite proud. But thanks for your suggestion.
cheers
Paul