I find Brixham fairly good
Steep, wide slipway - all states of tide
parking for your trailer at the top of the slip
parking for the car in the Multi Story MDL marina car park, just accross the road (walkway through to the marina) - Always planty of space and cheaper than the council one. You can pay in the marina office for multiple days
To the right of the slip (as you look at it) is the harbour wall with steps down which makes a perfect "pontoon" access
Ok - traffic can be a bit bad getting there in the middle of the summer, but last time I launched there for the weekend and went round to Dartmouth and I didn't have to pay for the trailer or the launch/recover
Harbour Master must have had the weekend off!