I saw a tv program the other week "City Gardener" where he used some
small electric heaters that looked like floodlight's. Just found out its an algarve 2 1.3kw electric heater costing about £140.

I know jumpers are an option but its just nice once it gets dark,
after eating outside to have some form of heat rather than all 5 of us
having to go & get jumpers.

The one thing i cant find out is how wide the path of heat is.

p.s Its about 3m deep, the heat that is.