Fruiting plum

I have a plum tree, variety Opal, which is approx 5 years old.

It is covered in fruit ( I'm not complaining!) but it is outgrowing the space available.

I have 2 questions please.

1. Each branch with fruit has approx 30 cms beyond the fruit.....can I prune this off now to reduce the size slightly?

( see photo)

2. As it is cropping heavily should I remove some of the forming fruit or can I leave it to have a bumper crop ?

I waited 3 years for it to fruit so I am reluctant to reduce the crop unless essential

Thanks in advance!