Fantasy..redsetter dogs killed by husband who leaves his dream life after suffering some sort og bre

I read this book while on holiday in Kos around '84ish, don't know if it was new or not. I remember a man, who worked in the city (possibly a banker) being met by his beautiful and successful young wife as he gets off the train at the station close to where their country cottage/weekend retreat was located. They had two much loved and adored pet dogs, which were redsetters and they referred to them as 'their boys'. They drive to their cottage and I think the wife pops out possibly for provisions. When she returns she finds the dogs with their throats slit and her husband missing. I remember there was some graphic detail about how the dogs died and of their terrified behaviour. I think the husband had had some kind of mental breakdown which had not been hinted at in any way and had come 'out of the blue', so to speak. He'd killed the dogs and the storyline followed his erratic behaviour. I think he's always aware of what he's done but can't help himself. He eventually joins a party of tourists, possibly abroad somewhere, who are being guided through a cave system. When the guide isn't looking, he sets off on his own, regardless of the dangers in search of something or someone he thinks he needs to find possibly before returning to 'normality'.

This is The Watcher by Charles Maclean. The same book came up in a recent query and LT user MyriadBooks pointed to another site where the query was solved.

You are an absolute star. I have not visited the Librarything site for while. I saw another post last night from another person looking for the same book. Thankyou so much. I have ordered a used copy for the princely sum of £1.11 plus p+p.Thankyou so much.

You're very much welcome. It wasn't me who solved the query (MyriadBooks did); I just passed the info along. But I'm glad to have been of use.