Well, solved that problem by cutting another hole in the back of the filter plate so the whole unit sits (off centre) 25mm lower.
Another question, I need something to switch my colling fan on/off and am wondering whether anyone has used one of these -
.
Thinking of glueing it to the front of the thermostat housing.
The only other option (cant find a T-piece to allow me to fit another sender into the single thermostat housing threaded hole anywhere) is to fit a hetal section with a threaded hole into the radiator top hose. But I haven't really got room!