I think the factory closed not long after Britvic bought Corona from Beecham products (Lucazade, Ribena ext.) Britvic only bought them to increase market share and soon closed most of it including the main plant in Brentford.
Hi there
Britvic also bought out R. Whites which had been owned for some time by Whitbread's. Incidentally I always thought syphons were unhygienic, let alone the swing tops. I remember filling them at R. Whites on one occasion when they were short of factory staff (I worked in the office). There was no way of washing them out, and they were filled through the spout
upside down. They regularly exploded during filling!
Kind regards
Dave