Wonder if anyone can help?

I am trying to grow some Gem Squash from South African, in growbags,
outside on a SSW facing spot in the garden. The plants are doing
quite well at the moment and have just stated to fruit, about the size
of a large grape.

Do you think I will be successful in growing them to there full size
in this climate?

Do I need to pinch the end of the plant off once thy have reached a
certain length to encourage fruit growth?

Just one more query.

Can I successfully grow Sweet Potato in this country, I thought of
planting them in a very large bucket type container and earthing them
up as the plant grows.

Many Thanks.

Regards.

Rick.

(From U.K.)