Thanks for the suggestions, will check that and replace the filter just in case.
BTW, when I say it takes a lot of cranking, I mean a lot (!) - it has been enough to flatten the battery on occasions.
Am I right in thinking that others have the same cutout switch, preventing the fuel pump from running until the oil pressure light goes out ?
I guess the other option is to start (& drive) it more often (!)
Not as far as I am aware, I am guessing you are in USA as European cars of this vintage have manual type pumps?