Not sure where my first post has gone?

In a nutshell I've used a Mazda 6 'flat plate' resistor unit (after slight mods) from an '02 reg TD to replace an earlier type (smaller) 323F BJ unit that failed.

Fixing screws were in same place but Mazda 6 plastic baseplate has a very small extra section that
needs filing off.
You need the plug from the 6 as well (with about 2" of wire) to splice/solder onto the 323 wires.
Same colours, just a slightly smaller plug.

Cost £3 and ten minutes work with glovebox removed for easy access.
Now the heater blower works on all speeds rather than just one.