I had it last year and it was ok from memory. It is a relatively low abv for what I drink in winter so I have to reset my expectations. Think I'll be happy to revisit 750ml again.
Got a feeling I have had the choc vanilla stout but might be confusing it for something else.
^ I'm buy two drink one tonight, the other one is the titanic grand reserve plum jobby.
They also have 2l swingtop bottles of the t.g.r.p.j, it's £30 and very tempting as I could re-use the bottle for my homebrew.
The siren is very big on the barrel flavour, v.nice.