My 14.2hh arab x welsh used to regularly clear over 5' and on a couple of occasions we cleared 5'6" (but that was just damn scary!!!) and Sovy was a truely exceptional JA pony. A 14.2 section D mare I had used to think nothing of 4'6". Usually native types can jump far higher than most people expect, it all depends on the pony's scope and how much they enjoy jumping! Remember there have been a few remarkable ponies over the years like Stroller (who I believe was only 14.2) that have won over tracks like the Hickstead Derby...
As high as his ability allows. 14yo is, for example, still in his prime if he were a BSJA jumping pony - many of them go on until they are in their late teens, if not older. There's a super one near us who is rising 27yo and for sale for 9K....
i had a 13hh pony that would jump 1.15 easy, it depends on if they want to, if they do want to and they enjoy it then most ponies will suprise you as they can jump very big.
Any height - have you see the height ponies jump at the highest junior levels? Bloody huge compared to their size! Don't 148's jump something like 1.30m? I used to jump 4ft on my welsh x highland 13.2hh which I thought was massive back then. But then I had a super 14.2hh who would win up to 1m but struggled jumping 1.05m courses.
I think any pony will jump 3ft and after that it purely depends on the pony just like some horses are scopier than others. You can't really say.
I never measured this fence but was about 12 years old, riding my little 12,2hh welshie and we set up a jump made of milk crates.... I remember there being 6 milkcrates stacked on top of each other!!! (can someone pleae go and stack up some milk crates and measure it!)
he cleared it!!! I only asked the once...... and even then I think I shut my eyes!
As high as the jockey wants to!!! My ancient (she was 19 when I got her!) 13.2 jumped 5ft plus in chase me charlie classes our best ever was 5ft6ins!! I am sure he will be fine with whatever you ask.