It’s been probably 10 years since last coming across these things. This house had 6 of these horrible mechanisms that had broken. (A massive garage spider was living in the frame of one of them). Most of these windows ever fitted broke years ago and have already been replaced. The Tallon system can be very secure but in reality it just means they’ll break and jam your windows securely shut.
With the correct tools and equipment it is possible to repair UPVC jammed windows and fit a modern system in their place. That is much cheaper than completely replacing the windows. Hopefully these will be the last Tallons we need to work on. I’d hope it was the last time a huge window spider runs up my arm but that’s been proved wrong already this week.