Here you go, seems covering with plastic bag overnight helps , just cleaned off and put another coat on remaining , so it does work, seems you need to scrape any good paint(scratch) to allow chems to be effective ,and leave over night to do its stuff.
so after leaving over the week end just washed off , 95% done , light clean with some scratch pad and its ready to paint . So it seems leave for 24 hr in a bag and it works fine , cost will be £5 on stripper , £2 per can of spray from £ shop(?) and only about 15 min (max)scraping each , what a few minutes to spray ? so a good saving on each rim compared to time spent , and also saving another £30 or more rrunning back and forth delivering and collecting . happy days