I returned to England last year after 6 years away - I was M6 when I left in 2013. Whilst abroad, I went through threshold/UPS (was working at Nord A school), and when returning, my current school in London accepted my UPS and were able to match my salary from China. My school is a state Primary but it just happened that they were looking for more experienced staff members at the time, so were clearly able to justify the higher pay scale appointment through governors. I was one of 3 hired at the time whose threshold passing whilst abroad was honoured. So I'd say yes, a TLR or threshold could still be worth it's weight - dependent on your school / the experience you gained abroad and what you achieved/how you sell yourself.