Historically the ab initio route has always been a Nats thing.
Smaller ANSPs don't normally offer ab initio positions. They'll maybe send you on a course if you already work for them (for example as an assistant).
If you're interested in an ab initio route outside of Nats, HIAL is probably your best bet.
Stornoway is not for everyone. Very remote and very quiet airport. But a job is a job.