Hooray! I can fly again
Called at a local Shop which stock the sabre and twister, and picked up a set of perkins blades for the twister.
I wasn’t to confident at first as a close visual inspection showed that they seemed to be the same as the first replacements, namely “polished” underside, and the mould around the mounting was also the same. Holding the blades together to compare showed that the pitch was the same as well.
Balanced the blades, and chucked them on and wow! A few great short low hovers, best I’ve ever managed actually. The dog was milling about though, and the light was failing so there was no time to take any vids.
I cannot detect any difference between the 2 sets of replacement blades which is a shame as it would have been useful.
My only recommendation is that in future blades are bought where possible from a local shop, where you can swap them if they do not lift. For the price of them, sending them back to an internet seller is probably not worth the cost and hassle.