You can either replace the HP gas hose re-using the old pig tails with new ear hose clamps (do not use jubilee clips) or buy a new pig tail like this.
https://www.acornengineer.co.uk/hp-pigtail-for-butane-with-1-4-bsp-coupling-nut-olive-with-non-return-valve
You can still buy the gas taps that allow you to couple to the Campingaz 907/904 cylinders and the 4.5 Calor butane cylinder.
This is route I went down with my Tilley Twinfold stove.
You can look up my post on how I did this.
I can't help but thank you for a trip down memory lane to my childhood as we had one of these stoves for our family camping trips. I also used it when I went bravely off to France with my then boyfriend (now ex-husband) to France aged 18... had a bad moment when some air must have got into the hose/connector and a big yellow flame jumped up from the burner and singed the mesh cooking panel of the Marechal tent we had borrowed from my parents. I threw sand on it (we were camped on sand near Dune du Pyla) to extinguish before turning off the gas! It did survive to cook another day but that was about about 35 years ago.
I hope you solve the connection issue, there must be a solution surely.
Looking at the Cadac Trio gas adapter, you could probably use it without its regulator if you can securley connect the gas hose to your stove.
The stove runs of a butane bottle at bottle pressure.
The originals post was 9 years ago and there have not been any further posts. It would be interesting to know if they tried any of the suggestions and lived to tell the tale.