My wife was ready to file UK visitor visa application on the day Regent House visa office closed due to redshirt actions. She had purchased the bank check to pay for the visa application but never got to file the app. She did get a Schengen visa (Denmark visa offices remained active a bit longer), is having a good visit in Denmark and now has no further intention to file for UK visa. So how to get the cash back for that check, which is made out to the UK visa service?

Try returning to the bank that issued it ?