I came to Australia in 2015 on a 457 visa, so it will expire in 2019. I'm too old to apply for PR as I am now 51 years old. However, myself and the wife would like to stay a bit longer if we can. I believe there are exceptions, e.g. salary level, but I would not qualify on that score.
I have checked my job title, and it is still listed on the medium to long term occupation list. I have every reason to believe that my employer would sponsor me as I've worked for them for nearly 10 years and they sponsored my transfer to Australia in the first place.
I am assuming that the new TSS visa fees (from March 2018) will apply regardless of whether already resident in Australia (on a 457) or applying outside the country, e.g. for a joint application with my wife for a new 4 year visa, then it would cost about $5k to apply and my employer would have to pay about a $7k levy, so that's a total of $12k. Age does not appear to be an issue, but obviously this is a hefty amount to part with (including for my employer) if the chances of success are slim. I guess what I'd like to prepare for over the next year is whether just to enjoy my remaining time here before going back to the UK, or go for it. On this last question, perhaps no one can answer.
I may have answered my own query above, but would really appreciate any advice on transitioning.
Questionable wisdom moving here at such an advanced age, but I've really enjoyed the lifestyle, even if it was only for a while.