From the brewery:

Stupid Sexy Suffolk is our base Flanders Red ale recipe that we’ve used in a number of blends over the years. Occasionally, we take a single barrel that displays stand out qualities too good to blend, and add fruit or hops to enhance them.

This particular barrel, which was a 2nd fill from a ruby port barrel, had lots of lovely deep fruit flavours, something that we thought would pair nicely with some local blackberries.
The result is a beer with almost a red wine quality, with those dark red fruits coming through with a touch of sharpness from the fresh fruit.