Battery! S Type 3.0 V6 2003 model

[John Heth]

I currently have a Bosch S4 013 800amp 95ah 12 volt battery fitted. I’m experiencing erratic warning light (ABS DSC and Park Break). When the park break fault is displayed the drive away locking, speedo and cruise don’t work, as soon as the park break fault disappears these function then return. The battery is only 4 months old but I did, inadvertently, let it go flat and had to re-charge it. I have had new rear abs sensors and an abs ring fitted because these were definitely faulty. So, when no faults the car is perfect but often the faults reappear. I know there are many threads about this but I did wonder should I fit 100ah 900amp battery - would that help? As you can probably guess, I have no technical/electrical experience. I’ve had the car for 14 years and still love it!  Many thanks in advance.