There’s another grp wound bottle marketed as Safefill which is made by the same company who make BP Gaslight, which now is marketed by Flogas. The Safefill is a DIY filling cylinder which some may not see as appropriate but the basic grp wound cylinder is the same as Gaslight. (See Hexagon Ragasco of Norway)
Be good if Calor follow the same path as Gaslight and with interchangeable fittings/regulators but that might be too much to hope. No doubt Calor are doing all necessary due diligence checks to ensure that any product sold by them is safe and fit for use.