I think the Viburnum beetle larva is the smaller one in the picture J52 has shown. The larger one is a ladybird larva which is eating it. There are different ladybird species with different larvae too. I’ve noticed that badly infested Viburnum tinus have a bad smell about them!
I agree with Davidhs. Mine (2 together) were easily 20 years old and very useful but you must get rid of that blight. First of all I tried cutting off all the affected parts, but when that did no good they just had to go. Sorry!