We have had a rather cool and wet summer which hasn't helped vegetables at all.
Pumpkins are very hungry plants and require lots of water, and the roots like to be warmer than other plants. If your soil looked wet then something was wrong with the soil/roots of the plant. The compost doesn't necessarily need to be fresh, as such, but you should tip it out and mix it up with a good amount of rotted manure, etc to make it very rich. In fact pumpkins grow beautifully on rotting manure because they just love the nutrients (and warmth).
If you put a mini greenhouse over the tomatoes they may well ripen even with the changing weather. They also prefer not getting wet so that would help them. Feeding does matter, your tomatoes are likely to be quite bland if they haven't been fed very much.
Not sure about runner beans, but TBH I think as a rule you need to either have fresh compost in a pot, or mix in a good amount of rotted manure for plants to do well - probably easier to just get fresh potting mix!