Upvote:-1
What you have is a Home office travel Document issued by the Swiss govt and as such I do not think you would need a transit visa (reference)
You donβt need a transit visa if you:
are from the European Economic area (EEA) or Switzerland
have an EEA family permit
have a Home Office travel document, for example youβre a refugee or stateless person
have a Standard Visitor visa
have a Marriage Visitor visa