Mini cooper s facelift: driven. Fast acting drain unblocker with granule soda used with hot water instantly opens clogged drains faster than any liquid drain cleaner. Choose an address from the list below... Yes watersafe will accept nvq level 2 as a minimum, accompanied by a water regulations certificate, but recommends s/nvq level 3, to be fully competent. Manufacturers recommend having your boiler serviced once a year.