I'm sorry Endaborg, I'm not at all sure what you mean by 'bolted' with regard to Begonias, that's a term usually reserved for leafy vegetables, can you clarify, or add a photo?

Leave them alone outside. The new leaves will be more compact.

Ah, you mean they've got tall and lanky - do as Steragram says, but these plants are usually in wall troughs or hanging baskets, because they trail. If you don't mind setting them back a bit, you could cut them by half and wait for regrowth.

If they are in fact the trailing ones you could perhaps just stand the pots on something to keep the long stems from trailing on the ground?

Actually Endaborg, I have a few like that, which I plant in containers, have done for the last few years and save the tubers each year. They haven't 'bolted', it's the type of begonia they are. They are pendular, in that the plants are upright but the flowers are pendular (the same as upright fuchsia). Common name, begonia 'million kisses'. Two or three of the same colour in a planter, (depending on planter's size ) are spectacular when in full bloom. Trust me!