Upvote:0
Apply for a new visa.
UK Immigration is well aware of the current situation and the difficulties that imposes on international travel - your current visa was issued with a specific intent in mind, and that intent was prevented by the pandemic.
Your previous denial is not an issue as you have been successful since then (if I am interpreting your question correctly). The fact that you have not travelled during the period of the pandemic will not count as a negative, nor will the fact that the visa expired unused during this time - UK Immigration is well aware at the best of times that plans change, and recent events have certainly caused plans to change.
Apply for a new visa, be open and honest when asked about why you are applying - if given the opportunity to explain, do so.