Something of a Paine

This appears to be the real Campanula garganica 'W.H. Paine'

Since 2010 I've been growing a rather pretty alpine Campanula with mid-blue, white-centred flowers and hairy, conspicuously lobed and toothed leaves, under the name C. garganica 'W.H. Paine'. It's shown below. I have no note as to where it came from, rather carelessly.

In the past few days a stunning, floriferous Campanula has come into flower, also in the sand bed (above). Its label also says C. garganica 'W.H. Paine' - which I picked up at Aberconwy Nursery last autumn, thinking it was just C. garganica (I didn't see the cultivar name on the label).

So which is which? Google Images shows both under the name (plus various other spurious options). The Alpine Garden Society Encyclopaedia of Alpines only says that 'W.H. Paine' 'has richer-hued blooms' (compared with the 'blue with a white centre' of standard C. garganica). In Campanulas, A Gardener's Guide by Peter Lewis and Margaret Lynch the description says it 'has a striking white base to the rich violet corolla' (and that it originated in Ireland). Graham Nicholls, in Dwarf Campanulas doesn't give much more of a description,  but his photograph shows this plant exactly, and the comment that 'when well grown it can conceal all foliage beneath the flowers.' On the strength of this I'm satisfied that this plant is the true 'W.H. Paine', and it is indeed a beauty, deserving its Award of Garden Merit.

The other one remains mysterious, not apparently fitting the description of any of the cultivars listed by these authors. It may be a form of C. garganica, but more probably a hybrid, possibly with C. poscharskyana (though it lacks the rampant vigour of that species). Suggestions are very welcome!

So what do I call this?