Is the water salty?
YES. ITS ESTURINE SO IT WILL BE SALTY JUST NOT AS SALTY AS THE SEA. I'D RINSE OUT AFTERWARDS.
Can you anchor somewhere quiet and have a picnic on your boat? VERY HARD TO FIND ANYWHERE F.O.C. WOULD SUGGEST DRIVING DOWN TO LIMEHOUSE BASIN (ACCESS 2HRS EITHER SIDE OF HIGH TIDE) AND LOCKING IN F.O.C. AND USING THE BARLEY MOW PUB INSTEAD.
Alternatively, are there any parks where you could moor up and go ashore and have a nosh your sarnies?
A FEW BUT THEY TEND TO BE QUITE A LONG WAY DOWN STREAM ROUND THE THAMES BARRIER/THAMES HAVEN AREA.
For more info look HERE
on the previous trip we did.