Early French beans from the greenhouse?

Next year will be just my third season with a greenhouse so I'm still working on how to get the best productivity from it.

I don't grow French beans outside these days as I've got limited space and don't really want French beans at pretty much the same time as runners, so am looking to try to get some early crops in the GH.

Soil will be 65L bags of compost on the floor, preferably the stuff already used for this year's toms (suitably enriched if necessary) - is this a viable idea and does anyone have any experience of how early it might be possible to start cropping, suitable varieties (dwarf or climbing) etc.?

I'd guess that it all depends on how much sunshine there is to warm your greenhouse and how frost-proof it is.

Sow a few indoors in late February for planting in mid March might work.

Climbing French Beans might be best if you can give them support - I would have thought they should give a heavier crop. Having said that I've had some huge crops from dwarf beans planted out "early" under two 3m long cloches on the plot but I am much nearer the equator than you JayG. 

I grow a variety of dwarf french beans called Speedy early in March, three seeds to a twelve inch pot, spread well apart.

They germinate indoors on the windowsill and then right away go down to the frost rfee greenhouse on the staging. They get covered up at night with fleece if the weather is really vicious.

Gives me a nice early crop about mid May,by which time they are outside if the weather is decent
 

You may have to teach any early bees to open and shut the greenhouse door .