There are a dozen or so smaller UK makers (smaller than Colgate, etc) & it could be any of them. Lornamead own Ingram's but have not moved production so far.
Bulgaria is very likely for the Erasmic. Amber house bought the formulae from Keyline & for some reason moved production, as the last previous batches were UK made.
Although Swallowfield bought RSC they have discontinued the Classic range & I'm not sure if they offer a lather cream either. The Traditional was always foaming, but brushless, & I have not tried the sensitive in this new range.