Hi Martyn and sorry I didn’t see your post until today . I was also in Bangkok last week (including the 13th) staying on Sukhumvit (I assume that’s where you are, given that you mention Nana and Soi Cowboy).
It would have been fun to meet up and commiserate about being away from our families! If you’re still there, I can recommend Kuppa (a nice restaurant on Soi 16, located in an old coffee roaster building) and also Long Table, a chic restaurant/bar on the 24th floor of a skyscraper, overlooking the park/lake (also located on Soi 16).
Perhaps a topic can be started where like ‘lonely’ travellers can post where they’ll be, on certain dates for possible meet-ups.
Chin up and best wishes!