Well folks, I got my tank well cleaned out, several bottles of vinegar and the shaking around of nuts and bolts, followed by a few blasts of the power washer. I also cleaned the pump as best I could, wriggled the gauze filter thingy off and cleaned it, cleaned the plastic netting bundle that was cable tied around the gauze, cleaned the electrical contacts etc etc.
Put the tank back on outside in the dark ( not enough room in the shed to get around the bike) with assistance from long suffering wife, half a gallon of petrol and a squirt of injector cleaner, hit the starter and away she goes, sounds sweet!
Major relief, thanks Art for the advice, I will be changing the oil and filter and other fluids asap. I have already found this forum to be a great help, no doubt I'll be back looking for advice!
Eddie