They are raised ground poles. Basically, a pole bolted to an X at either end that can be turned for three different heights (approximately, 6", 12", 18"). Very useful for strengthening and can be used to set small gymnastic exercises. Better than poles on the ground as the height makes the horse work harder and they aren't kicked out of place as easily. Also easier for the rider than trying to rig raised poles using jump wings, etc. as the are one piece!
We get ours from Coventry Fencing in Auchterarder, which is no use to you at all. If you don't get a more helpful suggestion, look in the Yellow Pages and find local fencing suppliers they may well be able to help. Or sawmills come to that.
I got my poles fron somewhere by Turriff. I'll find out exaclty where if you are interested (i.e. if thats close by) I think they were about 8-10 pounds unpainted
I am in Aberdeen City, so Echt is close enough. Turriff is a bit far, but to get the right thing at the right price, I could be convinced to drive there! Yes, Auchterarder is probably a bit far!
I have also emailed the Forestry commission to see if a logger will give or sell me a few of their nice straight, 4" diameter logs!
I got mine locally from a place near Insch, although might be a bit far out for you. He's very cheap as they're not meant as poles. You just have to sand them off a little!