Varta make Halfords batteries, so I brought a Calcium battery from Halfords for £65 (With trade card, retailed at £100 otherwise). I searched everywhere for the best battery I could buy and only ones better than this was a Varta battery (£96 and ONLY 2 Amp difference) and the Gel batteries (£150+)

Phone Halfords up and ask what they have in stock and the Amps that they supply. Escorts can take bigger batteries than standard

I had a Varta battery and 90amp alternator on my old S2 and never had a battery problem with a loud sound system. I need to uprate the Skoda alternator at some point to be safe