Rhododendrons

We have two bushes in the garden; one that I blipped on11th May which was in a sorry state due to Spring cold and this one which sits nearer the trees and is perhaps a bit more sheltered.  I think we brought it back from J's aunt's garden in Aberdeen so perhaps it's a bit more hardy.  it has taken about 10 years to flower, but it's been worth waiting for.  I had been wanting to cut the red one back due to the damaged leaves and also this one as it is tall and spindly, but today in the car I heard Gardeners World on the radio and as luck would have it someone asked the question.  The answer however was "Feel around the bottom branch of the bush and if it has rice sized "wee bits" on the branch it can be pruned.  If it hasn't, pruning will kill it".  I guess I'll just leave both of them as the bark on both is a bit rough and I can't tell if they can be pruned or not.