Adult Crime/Thriller - Ex-SAS, works in pub, investigates a poisoning in France, parts in UK/Ireland/France. Drug Smuggling Plot

[St. Oph]

Posting this on behalf of a friend:-

I read a book (Paperback) last year and cannot remember the author or title. I hope someone on here may be able to assist.

The main protagonist is an Ex Army(SAS) lives in London, works in a pub. I recall his uncle has some involvement too

The story goes that a young man is lured to a cafe in France and is poisoned with an untraceable drug, this is to facilitate drug smuggling over to the UK. The young mans step mother hears the news of her beloved and travels to the UK from the US and is in touch with a senior army person who knows the main character and puts her in contact with him. the story plays out where they travel around to Ireland then France and discover that the lad was murdered and it was for a drug smuggling operation.

I believe there is a series of books by this author and would like to have a look at the others.

[Lobstergirl, au gratin]

Can you rule out Ian Rankin?