Rethink Time.
I've decided to have another look at the chassis. It's going to be way too heavy for the job I have in mind. I'm going to use what steel I have to improve the storage in the shed and then start again with some steel tube for the bulkheads, it'll look a lot tidier too. More when it warms up and I can do a bit more than two minutes in the freezer. Note to self, if you ever buy another garage ,DO NOT buy a steel one!