Number of trusses?

I do get blight but it’s generally late in the year, October normally when everything is dying back anyway.

That may be due to the damp? I keep my doors and windows open as much as possible.
iI start hardy annual flowers in September and they would damp off if I shut the doors up and closed in the vents. 
My GH is 20ft long and is pretty tall so I think that makes a huge difference in airflow?

Scarlet, your in the same region as me, do you have heat in your tomato GH? I sow my toms around 20 March and still find they can get caught by late frosts without night time anti frost heat.

I carry mine in at night if the forecast is under
10. I have those big Gh trays and I carry the whole lot with someone's help.

My smallest greenhouse is only 8 x 6 with no automatic vents or windows just the door. The bigger greenhouses don’t have as much issues as that one but the border beds are better in the smallest one. Maybe be one day I’ll get a window for it.

I dig out my borders like JJB, water into pots and take all leaves off below the first truss. I do get blight but it’s generally late in the year, October normally when everything is dying back anyway.

That's what i do as well topping the border up with dalek compost then when my toms have finally finished I plant lettuce and chard to eat over winter. 
Mines only a 8x6 so I do keep the door and back louvre  open, roofs on a autovent hopefully all that through air helps.

Do you keep them open in the winter Bren?

Mikey there’re left open unless it’s either snowing or frosty, I grow either Arctic king and all year round lettuce both don’t mind the cold. When I grew salad bowl one winter that soon went floppy in the cold.

So a bit like my bedroom window then, only a holiday away closes that.