Do ask the supplier how long the doors will continue in production. We got caught, as we needed a door replaced under warranty, and there weren't any left, but it was glued back together.
We have a fan radiator hooked into our CH and it works well. I've seen under unit heaters, and wonder if you can get something similar. Might melt the flips flops though. Come to think of it, this sort of thing is now used in caravans