I'm Australian, but wanting to switch the Ancestry visa for the UK. Given the whole corona thing I'm struggling to get home without paying thousands as the airline messed up my original flight. My current visa expires in a few days so was hoping to go across to Germany or somewhere to switch visas as I need to have left the UK. I've called around but no one seems to be able to give me an answer.
Unfortunately, you can only apply for a limited list of UK visas outside your country of residence, which does not include the Ancestry visa.
You can make applications for a visit visa, a short-term study visa, an EEA family permit, Tier 5 (Creative and Sporting), Tier 5 (Youth Mobility Scheme) and Global Talent entry clearance in any visa application centre, British diplomatic mission or consular post overseas where entry clearance applications are accepted.
Applications for other types of entry clearance should be made in the country in which you are living.
A normal strategy for antipodeans in your situation is to apply for a working holiday visa in a European country which grants them to Australians, such as France or Ireland, and then apply for your UK visa from there. But if your UK visa expires in a few days, you don't really have enough time to do this, and most of these programmes seem to be suspended due to the pandemic anyway. Unfortunately returning to Australia is likely your only option.