I do not know if this is available in the UK or what it may be called if not the same as in North America. I have used yellow coloured Pine Sol with great success. In my case I am using it on well aged enamels which are also the older paints people seem to miss. This is because I have been stripping paint jobs done up to 40 years ago, both Humbrol, Testors and the old Pactra military colours. I left the pine sol for a week (I forgot about the models) and don’t know if that helped it work. The models have been mostly micro armour with very deep detail. You could use old tooth brushes to clean the guck off but my impatience won’t stand for that so I have been using steel wire brushes (about the size of a tooth brush made for god only knows what use originally) and using no protection for my skin. Wash off with water after.
PLEASE NOTE: Yellow Pine Sol is toxic to cats! My significant other was a veterinarian and that was the first thing she said. So store it way from cat’s ability to access if you go that way.