Makes sense. I'd lean towards a laptop, so does that mean you're happy waiting until your current MacBook actually starts showing signs of age? I know some people would prefer to go to uni with a fresh device, even if they don't need something new, just to be safe in the knowledge that it'll last them. I think it's unnecessary to replace a functional device that still does the job, but I can also understand why people feel that way.
Just to confirm, are you looking at buying a device in the UK or Australia?
Seems fine to stick with a MacBook then.
So this is a big part of the decision. iPads are getting closer to being a laptop replacement, but they're not really there yet. The note taking experience is supposed to be much better on an iPad, but I can't comment on that as I've only ever owned a Surface.
As far as tablets go, the Surface Pro is by far the best tablet that could replace your laptop. In fact it's the only device that I would comfortably recommend for offering both an excellent tablet and laptop experience. Everything else forces you to compromise on one or the other. However, if you'd prefer MacOS and the note taking experience is better on an iPad (I think you'll only know for sure if you try both for yourself), then a Surface Pro might be the wrong device for you.
With that in mind, my recommendation would be to go try them out in a shop. I typically recommend someone tries a device before buying anyway, but I think this is extra important as far as handwriting goes. If you try out both an iPad and a Surface Pro, see which you prefer and then use that to inform your decision. It could be that handwriting is really important to you, so you keep your current MacBook for working on and buying an iPad for note taking. Or maybe you consider it too expensive for a note taking device and don't bother.
I think replacing a functioning MacBook for the sake of it would be a bit daft. So really I think boils down to how much you want a note taking device. If the iPad does end up being the better note taking device then maybe you buy that for notes and stick with the MacBook for writing essays and the like. Worst case scenario, your MacBook gives up and you have to use uni computers for a bit or buy a cheap Windows laptop. There's no guarantee your MacBook will die of course. Maybe that concerns you enough that you'd opt for the Surface instead, since it could replace your laptop in a worst case scenario.
So I think you have 3 options, and it boils down to whether you care about taking digital handwritten notes enough to justify spending £1000 on a device:
1.
Buy nothing, and if your MacBook does die you've got the money to replace it with a new MacBook.
2.
Buy an iPad, focusing on getting the best note taking experience but keep your MacBook for writing essays. In the worst case where your MacBook dies, you could get by with the iPad but won't have the same experience as a proper laptop.
3.
Buy the Surface Pro, focusing on getting a good all rounder. The note taking experience might not be as good, but you'll have one device that does everything quite well. You could replace the MacBook straight away, or keep using it and the Surface ends up being a backup device (or it could even act as an extra display).
Personally, I'd opt for number 1. But I'm biased and wouldn't place that much benefit on having handwritten digital notes. Really, you need to decide which approach is best for you, because all 3 are perfectly valid depending on what you personally want. And I think you can only really come to a decision after trying out both the iPad and Surface for yourself