With our last van I had a set (2) of Babbington Leg Extenders which were steel tubes that went over the caravan legs and which extended the effective length of the legs. The extenders had foot pads to spread the weight. They were very effective as not only did they obviate the need for assorted blocks but they kept the legs outreach wide of the caravan and helped to stabilise it from rocking. When we "gave up caravans" in 2014 the Bebbingtons went with the caravan. The company are still in business but their product line does how the leg extenders, but as fabricators I am sure they might still make a set if required.
Here is the text of a PC post some 7+ years ago!
Hi,
for years I used wood blocks and other bits and pieces. Then after an article in the CC magazine I bought a pair of Bebbington Steps leg extensions. They are square metal tubes that fit over your steady and mate into place with the steady end. Then when you wind them down they just act like longer steadies. I would never be without them and a couple of years ago I lent them to family who were having problems levelling their van as the height of the front made wood blocks and stones not too safe. I left them with them and they posted them back to me. Here is the Bebbington website ...www.bebbingtonsteps.co.uk/
Read more at https://www.practicalcaravan.com/forum/equipment-accessories/38640-stack-a-pads-any-good#r8j7LbLuIwRA6q1U.99