http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=354#section2

The above link is to the RHS ceanothus page. You dont have to prune it at all. But it gives more advice too.

With buddleia I would give it a light tidy up now and then a main prune in spring, cutting it right down to the first budding point or two.

To be a bit more specific about the Buddleja (although the advice above is good):
now is the time to dead-head and reduce the height by about a third to avoid winter wind-rock.
The full pruning should indeed be in the spring, cutting back as it says above to the first growing bud, the exact timing depends on location and also when you want the flowers. For an average UK location mid-march pruning will give you flowers in July. But if you want the main flush in August for the butterflies don't prune until mid-April.

I dead head all of mine after flowering to get a second flush.
In the next month I will only tidy them up but not really prune until next spring

thanks to all x