Hi Robin,
I think the catches your looking for are like these...
Door lock fitting by
Sabrebuilder, on Flickr
I think from memory these are the ones........
https://stedall.co.uk/product/anti-burst-cab-locks-rh/
https://stedall.co.uk/product/anti-burst-cab-locks-lh/
I was surprised how expensive they are and the strikers are extra!
If you google 'anti-burst locks or latches' you may find others like these...
https://www.europaspares.com/anti-bu...-strikers.html
And I also found these that look like a bargain...........
https://www.ebay.co.uk/str/Moore-4-M...bkw=anti+burst
I also found this article that you may find interesting.........
http://morganrebuild.co.uk/RemovingDoor.html
Oh the joy of Google!!
cheers, Peter