Mercurial out of date and update doesn't work

I have Mercurial 3.2.3 installed as part of the installations which was done at the time the PC was built

I updated to Mercurial 4 as the System version 

Try selecting Use System Mercurial and the dialog pops up about the old version and after clicking ok nothing happens

Try to update Embedded - Machine is behind a proxy; proxy settings are correct and I get a Proxy authentication required error after putting in proxy details to the dialog which pops up. Went through resetting proxy password in general configuration and it still fails.