Old John:
Not sure who if anyone makes “proper” ones anymore.
You could probably find some “Lake and Elliot” jacks on eBay or some such place. They will have beèn made in the 50s or 60s, or before, in Braintree, Essex, but they last forever.
Proper job.
Yes I’ve got a 40 t lake & Elliot it was my Grandads going back to after the war ,quite what he was lifting I don’t know he never had owt bigger than a 4 wheeler 
,a Sealey 20 t is ample for me in the lorry should I need to put the spare on .