Fantastic channel only problem is the Fella does not tell you what is amiss. So that VDO does straight to the bin.
Point 1
When buying a new battery check the date and try and buy one from
a shop that has a good turnover in batteries.
In other words don't buy one that's been sitting on a shelf for a few years.
Point 2
Check the weight of the battery to see if your getting value for money example the battery listed above
weighs 20 kg a Halfords 100 ah weighs 30kg
For the price of the one above you can easily get a battery that weighs around 25kg that's 5kg more of material
such as lead.
Smithie sorry for highjacking your post just trying to be helpful.