Thanks, the ceramic heaters make sense if they are just as safe and take up less space than the oil filled. I'll look into those.

We have a propane on-demand hot water heater on the boat, which we love, so providing power for that is not an issue. Besides the ceramic heaters, our only shore power needs will be a dehumidifier and a 12V trickle charger, neither of which will draw much.

I just bought the 220V electric cable today. The cable is rated at 16A but the round blue plugs are only rated at 13A (which I understand is also the limit on the dock power). Wouldn't two 1500 watt heaters be pushing the capacity of the dock system? Or do you just assume they'll never be run at highest output? Also, did you have much issue with condensation?

We are probably going to winter at Ipswich Haven marina. We visited last week and like the small-town feel, open air market every day, nice lap pool for swimming, friendly folks. It's an hour train from London. We did visit St K's and it's tempting, but they are reluctant about doing winter rentals. Even if it turns out we can go there, we will probably opt for Ipswich. We plan to do a lot of land traveling, so will be away from the boat, and we have spent quite a bit of time in London in previous years.

Thanks again for your input (and everyone else)
Max