ABI calcium "marine king" battery issues

Had an issue last week with a battery, bought new on the Friday, from the dist of these batteries, [one size up from n70zz] it was one of the good maintenance free calcium batteries, and after staying at a friends house on the fri night last week, then going 4wding sat, the battery started to leak a black gell type acid out of one side vent, enough for me to notice it by the acid running down the chassis rails and inner fender while letting down the tyres, washed down the area with water, but the fan had blown it around under the bonnet.

Have checked charge rates, and have another battery in the car, which isnt having any issues, and was wondering has anyone else had an issue with these batteries as the company supplying them isnt being good to get along with about resolving the issue.?