A few years back, there were a couple of cases of groups of firearms being found in a Somerset river. However, the police said the ID's given by the finders were wrong/
“It was thought that the weapon parts could have originated from various weapon factories which were operating during the second world war.
“Suggestions that the previous find contained weapons such as Kalshnikovs and Uzis were dismissed as Avon and Somerset’s force armourer confirmed the badly rusted parts were thought to date back to between 50 to 60 years and therefore not those type of guns.
“It is believed that this is the case this time and the weapons are to be examined by the armourer prior to destruction.
And who says our police don't have a sense of humour
I somehow doubt this was an IRA cache. My guess would be this lot turned up in the attic of a deceased relative who may or may not have been involved in something even dodgier than unlicensed collecting of S.5 firearms. There also seem to be very few complete firearms, few appropriate magazines and no ammunition. The weapons also look like they've either been burned (except in a few cases) or have been underwater a lot longer than since PIRA decommissioned. Believe it or not, there were quite a lot of AR10s in private hands here prior to 1988 - one dealer had a former church full of them, and they still occasionally turn up.