In reply to jezb1:
Hey Jez,
Trango Tower is probably the direct replacement. I reviewed a pair, and found them slightly clumpier.
Trango Cubes have a very similar fit, but are stiffer. Amazing for big boot rock climbing. A friend described them as Fiveten Whites for big boot rock climbing. I’ve had a couple of pairs.
Outside have a killer deal on them currently.
https://www.outside.co.uk/la-sportiva-trango-cube-gtx-mountaineering-boots....
A slight curve ball suggestions which are great value are Kayland Cross Mountain. Very similar fit and last to the old Trango S. You can buy them from Crib Goch in the village.
HTH