Thanks Gary and others- sorted mine out the same way. a bit of a tight squeeze but managed to extract the pump and pipe despite my big fat fingers!. I used a tiny screwdriver to free the tiny fan on the end of the pump - did the trick. I squirted a bit of mouldew / bleach remover on the fan before replacing the pump in the tank. I also ran loads of water through the system to clean out any remaining bits of gunk that had obviously found their way in! Saved me taking my motorhome 'Priscilla' to a service place who would have probably charged for a new pump and a couple of hours labour for the privilege! Goo luck fellow motorhomers!
Danny - Burnley, UK, July 2014