If they work for you crack on but there hardly quality are they and if they leaked you shouldn't be surprised,I would rather buy and use things that are going to last it's all only an opinion on here take what you want from it if we didn't give an opinion on threads there would be no forum.Im telling the bloke to buy the right thing for the job so he's not down B&Q every 5 minutes.
Nearly 13 years with a leak free system, I'm not down at B&Q every Five minutes either mine last months and even years. However, they are readily available should anyone need a replacement, best of all is the best ones by far are B&Q's own brand at just £1 each and replacement "O" rings are just a couple of quid per hundred from ebay.
I'm only telling the bloke that he has no need to listen to you, as you are clearly not in a position to advise!!