App Store draining battery after iOS upgrade

Since updating to the latest iOS my battery drains very quickly. Full power to 10% in about 14hrs whereas before I could possible eak out 40hrs+.

I have not changed my usage or downloaded any more apps just iOS update.

Looking at the battery performance the main app that is draining power is App Store (approx 45%) but only 2m in the background (and I haven't used it). The other main apps are Audible (20% / 1:30) and Strava 17% / 1hr).

Conversing with Apple Support Chat they said 14hrs battery was about right (which I cannot believe based on my use and past experience). They also said I need to take it to a Apple Service Centre.

Before I do that or consider a full reset/restore: any ideas what is going on with the App Store draining my battery as I suspect that it is causing the issue.

Cheers