Tech Air has been taken over by subsidiary of Air Liquide (French parent). They are not involved in CNG. The only relatively widespread use of CNG is for vehicles, especially buses and the like -- meaning State and local govt. Such local sources here are very reluctant to get involved with a cylinder for a boat, even if it has been properly pressure tested and declared OK. One guy explained that it is a matter of liability (lawyers again).
I acquired CNG, with a Catalina 27 attached. Large bottle. Works well and doesn't seem to use much for v limited on board use.
I am used to high-pressure oxygen cylinder use in aviation; as already explained succinctly here, lighter-than-air CNG is a lot less dangerous, compared both with O2, where a leak can lead with a spark to uncontrollable burning rates, and especially propane which is heavier than air so leaks concentrate in the bilge until get to explosive levels. That Yachting World demo should be included in all boat training courses (hint to ASA and USSailing).
It should also be seen once a year by all sailors (not that there is anything like aviation insistence on some sort of repeat safety exercises for boat use, and even the aviation versions can be, and are, criticized as minimal).
I will now try to find someone who is knowledgeable about substituting methane from available industrial suppliers. Interesting suggestion .... thanks.
