Thanks for all your help chaps.
I had a bash at colour enlarging last night, and found that a 6x4 print from a well exposed 35mm neg took 35 seconds at f8. Obviously when printing at 6x4 the enlarger head was quite close to the baseboard which helped with the focussing and composition. Does this exposure time seem a little long?
I tried the experiment as suggested and found that the in / out arm on the left hand side DID move the filters in and out of the light source. However, when set to Ďoutí and with a fully opened aperture (f4 on this 50mm Minolta enlarging lens) the light coming out was far from bright. Would you suggest buying a lens that can go to f2.8 for compositional purposes?
In addition, I wondered whether there might be a more suitable focusing tool than the smaller of the two Paterson focus finders for use with colour? Itís fantastic with B&W but doesnít work a jot with colour.
Although Iím very frustrated that the head still seems to be defective, I was very pleased with the quality of the 6x4 prints mentioned above. RA4 prints seem to have a very attractive softness and subtlety to them which is most agreeable.