On notifications - This could be due to your mobile phone network - If reception is not great then the spending notification will only come through when you’re connected again. This behaviour should be same on Starling.
BTW - Let us know your thought in couple of weeks on this comparison. I closed my Starling account and never really used that much to have a fair view. I could not bring myself to like their UX. Monzo has much better UX IMO.