Hey mate,
Final year Scottish LLB (4 year degree) student here. I might get a bit carried away so I'll try to split my message up into different sections for the sake of clarity!
Eligibility
So in terms of when you can apply from, you are correct in thinking that, for most Scottish firms, you can apply from your first year of the accelerated degree/ third year of the four-year degree. However, this is merely an option not the 'make it or break it'.
In my own case, I applied to only a couple of firms last year (my third year) and ended up reaching one AC which I was rejected from. I did feel really stressed out and felt as though it was the end for me but I was definitely wrong! This year I broadened my target firms, refined my app technique and have ended up securing two vacation schemes in Scotland (one international firm, one top-tier Scottish firm). If I can do it, anyone can, so please do not worry if you fail to get a vac scheme this year. It seems to me that around 50% of applicants who go on to secure vac schemes/ TCs in Scotland actually do so in their diploma year (Scottish equivalent of the LPC/SQE) after their degree so you have more than time.
Firm Recruitment
You are right in that most international firms in Scotland do recruit two years in advance (think DLA Piper, Pinsent Masons, CMS etc). However, I have had friends who have been asked by their firm to start their training contract a year earlier (2022 rather than 2023 as was initially stipulated) so it is definitely not impossible. It seems as though most candidates who hold offers for such firms do tend to have other offers too so there is sometimes the business need to ask people to start earlier if they pick elsewhere. So please don't get put off by this, firms will likely try to accommodate your circumstances if possible.
With that, most Scottish firms do actually recruit one year in advance (see next paragraph re this).
Firm Choice
I note that you are mostly interested in applying to large international firms who have a Scottish base. This is absolutely understandable, likely higher salaries, international secondments, cross-border work etc are definitely strong pull factors. However, have you actually had the chance to attend any events/ talks with leading Scottish firms? Although not 'international', Scottish firms such as Burness Paull, Dickson Minto, Shepherd and Wedderburn, Brodies (among others) do carry out a lot of international work, particularly in the transactional teams. In fact, these are the firms which the US/ MC city firms will rely on to act on any Scottish elements of deals so you would have great exposure to international work.
I really do recommend you broadening your targets a little (as I did). Many of these firms host open days, attend university law fairs and interacting with them may actually change your mind! Ultimately it is your choice but I do think that broadening my targets did help me this application cycle. Further, as briefly mentioned above, the majority of Scottish firms will recruit one year in advance. Therefore, if you were to apply for placements/TCs with them in your final year you would be able to start a year sooner than with international firms.
Vac Scheme vs Training Contract
If you are yet to apply for some of the international firms I would recommend looking at whether they offer direct training contract applications. Firms like Addleshaw Goddard and Pinsent Masons typically recruit ~60% from vac scheme and the rest from direct training contract applications (I know people who have done so for both). Therefore, it definitely is worthwhile to submit these if you have the time and it interests you. Given you are a career changer and have much more life/ professional experience than most of the firms' talent pool you may be well suited to pursue the direct TC route.
I hope this helps, I'm aware it's a long ramble! Do let me know if you have any questions/ would like any other insight from me on anything re applying in Scotland or my own personal experience. Happy to share as much info as possible and give you a hand!
