UPDATE
Got the gearbox gaskets and seal come through yesterday.
Slightly jumping the gun as there is a chance the gearbox will be further damaged. Although I did contact the seller and asked him to confirm the condition of the box when he sold it to me. He did state that he personally used it and drove it to make sure it was ok.
If it turns out that the rest is ok then the new gaskets and seals will come in handy.
Weather forecast looks a bit dodgy in the coming week so hopefully it holds out for a couple days so I can get it checked.