The Dan Brown book has now been read cover to cover - very much a good book in my opinion. From memory, would say that it is on par with Angels & Demons and far better than the DaVinci Code.
Have come to the conclusion that this is because Angels & Demons and The Lost Symbol are equal parts science and religion unlike the heavily history adorned DaVinci Code.
Had some good news from the GP - the "all clear" but like all good news, it tends to herald the arrival of the bad. The black could which defines the purpose of the silver lining.