Hello Arron,
Just as Cliff says.
It’s a bit like having toothache and being told the tooth needs attention, then asking why you have toothache. Apologies if this appears rather harsh, but you know what you have to do.
You will obviously find you have choices when you come to renew the battery, and you can buy at the lowest price and be told you have a 3 year guarantee, or you can buy a good battery at the most competitive price - sometimes there isn’t an alarming difference between those two, if you do your homework.
For me, I only buy Varta or Bosch, and choose their 5 year guarantee range rather than the slightly cheaper 3 year. On line suppliers with next day delivery include Tayna, Batterymegastore etc. - there are more. Just search EBay and the seller will advise the correct battery when you give them your registration number. Batteries work hard with modern vehicles, so worth buying once and wisely.
Kind regards,
Gareth.