Gas cylinder fittings frustration

Whilst browsing Weber gas BBQs today in B & Q I noticed that the one I want comes with a 27 mm clip-on regulator which is fine as I have three BP Light (now Gaslight) cylinders. The reason they are supplying this regulator is that Calor patio gas has this connector. Of course the regular calor cylinders that we all use (and I have two of them) have the old fashioned reverse thread connector for which you need a spanner which you have to tie on to the cylinder otherwise you can never find it.

its all very frustrating and why on earth the BP Light cylinders never quite caught on is a total mystery. The lightest on the market, transparent so you can see how much is left (unlike the Calor indicator which goes from green to red just prior to it being empty) and the clip on adaptor which Calor supply but only on patio gas. The whole market is a mess!