More pruning questions

I'd wait to prune until autumn.

Ribes (ornamental flowering currant) varieties in flower now, prune immediately after flowering, taking off enough so you don't need to do it again till next year. Like Forsythia, Ribes flowers on the previous year's growth.

Viburnum, which variety? and is it a hedge or just a single specimen shrub?

Thank you both. I can't remember the variety but it's just a single shrub. It's supposed to be evergreen but does lose about half of its leaves each winter. Last time I tried pruning it, it didn't produce many flowers the following spring. Last year I left it alone and this year it's flowering profusely, but I'd like to trim it a little. I've added a photo showing both the Ribes (pink) and with the Viburnum on the extreme right.

As the Viburnum is a single specimen, the advice is to 'cut out some older stems down to the ground in early spring to encourage regeneration'. Not much help to you really - if you're going to prune, do it immediately after its flowered - I'd trim back the branches which have flowered in particular, to try to keep the size in check. Can't tell which one it is from this distance either...
Very attractive border in that photo though...