Yes, it does indeed look like you need a new battery given the age and you are observing readings below 12v if the meter is indeed accurate. A lot of owners here have reported replacing the original battery before the car's 6th birthday.
fwiw, eurocarparts doing 15% off batteries with BATTERY15 discount code. A Bosch S4018 battery is around £53.
Many owners including myself have changed the battery themselves, or visited to Halfords to get them to change it. Afterwards, all you then have to do is reset the front electric windows limit switches, and take car out for a drive on mixture of roads to help reset the CVT.