Cecilia and Sol: Dolce Duello(Decca)*** (3 of 5) I am about to break another of my hard-and-fast rules. A while back, I swore never to give another three-star review as long as lived on the grounds that such things are cop-outs for critics who cannot make up their minds, one way or another, about the recommendability of a record. One way or another, I stand by that judgement. So why the exception?The present album brings together the super-mezzo Cecilia Bartoli, the highest-selling diva on record since Callas, and Sol Gabetta, an Argentine cellist of mostly German acclaim.  The flirty-flirty cover, and some even more embarrassing social-media video, suggests that the pair get on rather well together across a generational gap. They are accompanied by a Capella Gabetta, directed by Andrés Gabetta, adding to the general cosiness.As for the music, it consists of Baroque arias that Bartoli sings exceedingly well, with Gabetta coming right back at her on a 1759 Guadagnini cello that was made just for this sort of entertainment. Only one of the arias is a blockbuster – Handel’s Cecilia Ode; the rest are jolly good cuts of Caldara, Albinoni, Vivaldi and others, done to the point of listener fatigue. There is absolutely nothing wrong with this record. It is as good as it gets, until you realise that you can get too much of a good thing.The trouble here is that this record is neither one thing nor another, neither a diva showcase nor an illuminating musical experience, nor even a shameless Christmas stocking filler. It is the kind of release that sits so squarely on its fences that it positively cries out for a three-star ho-hum rating (and I’ll try never to give another).The sleeve-notes, by the way, are uncommonly well written. And the Guadagnini displayed on the cover is a fake.___Norman Lebrecht has written 12 books about music, the most recent being Why Mahler? He hosts the blog Slipped Disc, writes a monthly essay for Standpoint magazine and is writing two more books.