Thankyou for all the replies all those last comments made us feel better!
It's going into a local garage tomorrow

but we definitely want to learn more basics ourselves and this forum is so helpful!
Just to make you feel better again I have rebuilt mine three times (chassis replacement, rebuild after an engine fire, conversion to a station wagon with the last two well documented on here), and mine still leaks. Currently from the steering box!
I bought my 110 at 18 and as a student (best use of a student loan ever) so I had a very steep learning curve as I couldnโt afford to put it on a garage. If you want to learn the basics these are the perfect vehicle to do it on and the forum is full of friendly and helpful people. Do not be afraid to ask silly questions (like what/where the diff is) someone will always answer.
I would start as above by checking the gearbox (fill plug on the side) the transfer box ( fill plug pictured above) and the diff (fill plug pictured above) oil levels. As mentioned all are full to level which means you put oil in until it leaks out the fill hole. This will also give you a little bit of confidence that working on the vehicle may be dirty and heavy but is not difficult.
In terms of the tools to do the job:
1/2โ open ended spanner (can use a 13mm at a push if careful not to round the square plug)
1/2โ drive ratchet
Maybe 1/2โ drive extension bar
Oil required to top up (a can of worms people like to argue about)
Diffs: ep90 gear oil
Transfer case: ep90 gear oil
Gearbox: ATF
If you are just starting out and donโt have any tools the large Halford advanced 200ish piece box set is a good starting point as it comes with a life time warranty. Everything else my advice would be to buy as you need it for a job and build up tools that way.