Sounds as if there aren't any leaves left from earlier in the year to inspect, unfortunately - did you notice any leaf symptoms, in particular, anything on the undersides, specially either side of the veins? Did you notice plenty of ant activity on the plant? Any sign of sooty mould when it had leaves? What colour are the 'little nobbles'? Any chance of a photo?

Thank you I have attached some photos of the twigs which have the nobbles.

Well it looks and sounds remarkably like a heavy scale insect infestation - if the plant covers your house, then you've a problem, because the solution is to spray thoroughly at the right time of year with something noxious like thiaproclid (Provado), which also kills bees. No point in spraying now, you need to treat when the nymphs are hatched and present, and they're usually on the backs of leaves - the fact that the adult scale you pick off the woody stem crumbles means they're already dead, and nymphs (immature scales) won't be present at this time of year. The other option is to cut the whole thing down to the ground and let it grow again, keeping any eye on it for signs of further trouble next year.