Welcome to Minor ownership, I hope that you enjoy every minute of it.
People often talk about oil in water and water in oil, but in my experienc3e, the commonest head gasket failure is between two cylinders. The oil might just be thin, if it had lots of water in it then it would be milky and emulsified. Look in the radiator, again you would see milky deposits. With the engine running and warm, a failed HG would probably pressurise the radiator and you would see bubbles forming in the water - be careful of hot, scalding water. Failure between cylinders can be heard as a loud popping sound and the engine will run very roughly on only 2 or may be 3 cylinders.
One of the best tools that you can buy would be a compression tester. They are not terribly expensive and will aid diagnosis of a number of problems, including HG issues. If you buy one, then post back for more advice on how to use it and interpret the results.
Brakes are a safety critical issue, so you do need some skills before tackling them, but a sticking wheel cylinder is usually fairly simple to replace, but it depends on what else might need doing too - it could be a brake hose problem, poor return springs, badly assembled components etc.
Does the car pull up in a straight line? Raise each wheel in turn off the ground - observe correct jacking and safety procedures, and then spin the raised wheel. Note if any make an odd noise or feel stiffer to turn, or generally do not spin freely.
I might split this thread into two separate topics so that you can concentrate on each set of replies, but I'm going to have some dinner first
