There is some made by a firm called Morris. I bought some at Pepe Boatyard, Hayling Island but i don't know where else you might get it. Try googling "Water Pump grease"
I see the ebay listing for Keenol,isnt Keenol,its Ramanol. I suspect the real stuff had something in it that the HealthSafety didnt like. Ill try it anyhow.
Last 2 boats had sail drives, but the last prop shaft job used Cannery Grease, as used in the factory canning food.
Water resistant because of frequent washing down I suspect, anyway that's all we put into the stern tube for many years and never had a problem.
Cost was lower than anything with 'marine' printed on it too. Just check the specification and compare to 'marine' labeled products, I suspect the only change the label having 'suitable for marine use on it.
Just bought 500g of Unipart Marine Grease from Aladdins Cave for £4-49, described on the tin as "A high quality calcium based multi purpose grease, ideal for marine applications with water resistance and low water wash out properties to protect against corrosion ..... for engine controls, winches, stern tubes, prop shaft bearings and splines, exposed deck fittings and boat trailer bearings"