Spot on Freddie - and a good link Also possibly easier for a "competent DIY`er" to do the metalwork - @ a real push it could be done with a hacksaw inserted through a small elongated hole ,take the blade out the frame - pass through the hole and replace frame - Pillar drill would be nice for the holes . I used to do a bit of metal bashing , making brackets etc for a trike I used to have . Lifted up a drain gulley that was outside my garage ( one of those heavy iron roadside ones hinged @ the back) and used it as an anvil