Hi Stalled Haggis, and welcome to pprune!
You raise a few questions which are not uncommon.
There are only three schools in Scotland which teach NPPL (M) on three-axis aircraft. Perth uses the Eurostar, as you have already found out, Keith at Balado (which you'd drive past on the way to Perth from Edinburgh?) has a brand new Eurostar, a brand new C42 and a brand new Skyranger. And we at Strathaven have a couple of C42s.
There used to be limits on what could be hired and used for training and how many could be in a syndicate. Training used to have to be on factory-built microlights, but again, there are now exceptions. So while things have changed a little, flying lessons are mainly on C42s and Eurostars.
So, if you are learning, it will be a high wing (C42) or low wing (Eurostar). If you have a preference for which type you might want to own in the future (high wing Skyrangers are very popular as first aircraft) then you might want to start on a C42.
The second is training on your own aircraft. To be frank, we are never really keen. First, we like to know the aircraft - we've been around for so long that we think we have seen everything that can go wrong, and then we discover something new! And we refuse to touch anything unless its got a Rotax 912 engine. And as a solo student, we are responsible for you even though we are not in the aircraft.
To be really frank, as a student, you'll not have a clue what you are buying!
There are also economic arguments. You'll be paying insurance, hangarage, fuel, maintenance etc for your aircraft, which will add to your hourly rate after paying the instructor. But for the instructor, they will be paying (or should be accounting for) insurance, hangarage, maintenance etc - but not fuel - for the school aircraft which will be sitting idle while you are in your own aircraft! So lose/lose for both parties!
Finally, your budget. 10k. You'll not get a decent three-axis microlight with a Rotax 9 series engine for less than 20k. And trust me, you'll not want a two-stroke one. Or a Jabiru! We now refuse to have anything other than Rotax 9 series powered aircraft based here at Strathaven, except in special circumstances. We want to save people from themselves!
But if you look at a decent Skyranger, perhaps with older-style Dacron wing fabric with a few years left in it, as one of three members in a syndicate, then you'll meet your budget.
Finally, there's the question of hangarage. It is in pretty short supply in central Scotland! I am not sure if there is any at Perth or Balado (I know Balado has a planning application in for 3 hangars). We are getting near our capacity here at Strathaven, Cumbernauld is full (and charges £6,000 a year + VAT!).
So you might want to answer the question low wing/high wing first, then who trains on it and then where there might be space to hangar it.
Or Perth hire out one of their Eurostars - so you can train and fly the same aircraft. And use that 10k to pay off some of the mortgage!
Learning to fly is a serious investment in time, let alone money. So well done for coming here and asking some questions. You should then use that info to ask questions at any schools you might consider too.