They are more useful and a lot stronger. But as one guy noted, if your place is domesticated, skid loaders will tear up grass. Telehandlers will not tear up grass.
So, a cheap Lull is $90k, and doesn't mow/bushhog/"top", is a very odd machine to pull a chain harrow, is very heavy, leading to compaction or rutting.
Now, 100% a Lull/Telehandler/shooting boom forklift is an excellent tool, as are skid steers, but not for the OPs situation. He needs an affordable horse pasture maintenance machine; and if I remember right, he needed/wanted a loader. So, I agree the 25-4hp tractors are the right class.
He uses small squares for hay, but without knowing the UK, it probably is wise to build in the option to handle 4x5 rounds? Horse hay may not even be available there in rounds, and I am not familiar really with the large cubes, but I'd guess 750-1200 lbs or 300-500 kg.
Frankly, a YM2000 sized old Yanmar would likely work; but it would be slow.
How is the small used impliment market in the UK? Are used 48-72" mower available?
What i will say, yes, a Telehandler and Skid steer are Miles (or Kilometers ahead for our OP) of a small tractor for loader work, but for moving manure around, he likely is ok. If you get something in the small utility size, I think you will be fine with 2wd, but I don't know how soft your soils are. I do think you want/need power steering.
On impilments, are you thinking PTO or ground driven manure spreader? I haven't really seen a PTO driven, but I know they exist, just don't know HP requirements.
Not pushing the brand, but I think my Kioti Ck2610 would do everything you describe, but would be maxed out with a 5 ft cutter.
The post driving, you will need aux hydralics on all of them I have seen, possibly 2 sets of rear remotes, but i think some may only need a single set?