One step forward two backward.
Fitted Bimini cover last evening, delighted with extra facility.
Returned this am to find I'd left the toilet sea cock open and the cabin was flooded.
Started to pump out useing the manual bilge pump and pressure dropped off.
Stripped pump down (very inaccessible) replaced stuck valve; worked perfectly for a while and now stopped again.
Will need proper overhaul.
Such is life