Just wondering if it is too late to sow mangetout?..would i get a crop or not?
Are we talking mangetout peas or beans (or something else) ? I tried a late planting of beans last year but they didn't flower, even though the plants grew as expected. You may just have a chance if you've got a well-lit sheltered spot, my plot is rather shaded ... try a couple of each of a few different varieties (if you have a choice) and use the results as experience for next year, with a bonus feed or two if you get lucky ;)
I've been so pleased with my Oregon Sugar Snap this year that I'm trying a late crop - I sowed in a tray last weekend and they are already through. I don't see why it shouldn't work, I grew late French Beans last year after someone on here suggested it, and that worked. Give it a try!
If you have spare seed and space and can water its worth a try. Assuming a rerasonable autumn you should get a crop, if not think of it as a green manure. Oregon Sugar pod is a good over-winter crop if you have a greenhouse and is hardy enough to try over-winter outside - in which case wait until November.
I think it's worth using up spare seed and filling space as much as possible and if you get a decent crop as a result it's a real treat.