Hi Owen, welcome to the wonderful world of motorcycling, you need a good pair of gloves first off, choice is yours of wearing a pair of trousers all day long or over trousers and jeans underneath, jacket with a good armour (back and arms) and as you live in sunny Scotland you will also need them to be waterproof. As to cost well as you have already said the price is really "what are you prepared to pay"? Buy the best you can afford is the simple answer. Leather is good but leather trousers are heavy and sweaty, boots are one thing you should buy that you spare no expense on £30 pair might be ok for one year but make sure they are long not ankle boots, other than that just get what you can for now, you can always buy something else next year. One thing tho, you have no fairing on your bike so EVERYTHING is going to hit you right in the face which means your going to be sitting in a puddle of water every time it rains so make sure the trousers are waterproof at the crutch, nothing worse than turning up for a night out with trousers that look like you've pissed yourself.
Just one other thing mate, might be good to pop over to the New members section and say "Hi" folks are wary of one hit wonders.