Try hythe marina it is a marina with lock gates so good security and has car trailer parking also they have a hotel in the marina as well.
I have no affiliation with hythe marina just walk the dog there a lot and I also launch off the public slipway at the marina.
I'm sure they do a weekly or 2 weekly deal as well also slipway is free to use at hythe also your about 600m away from WOT no endless river transiting