You are absolutely right, Ecotricity have the most awful reputation. There are rapid chargers at Birch services - I tried them once but they didn't work.
Your best bet is to download either Zap Map, or Plugshare apps, or both.
Zap map allows filtering where you can specify certain criteria which includes which specific suppliers you want to find.
If you use Apple CarPlay, then Plugshare is available on the CarPlay interface, which means you can search around you for chargers on the in car display.
There is a third app called 'a better route planner' (ABRP) which enables you to plan your journey ahead, plugging in all sorts of parameters, and it will help you locate the best stops to charge. It is also available on CarPlay if you pay the monthly subscription for the full version.
In reality, the charger infrastructure in motorway services areas is simply not where it needs to be right now - there are lots of threads on here bemoaning that fact and it has been widely discussed recently because the govt is inviting EVs users to participate in a govt survey to feed into a consultation exercise (i.e. a 3 year talking shop with little action).
In the meantime, you would be wise to take the default view that Ecotricity are awful and are to be avoided. It will lead to a less stressful ownership experience. There are other better options, you just need to plan ahead. Many people stick to using Instavolt and Osprey - 2 of the most reliable networks.
If you stay in ICE mode and think that the motorway service areas are going to serve your needs, it is only a matter of time before they let you down. Always have a plan B.
Enjoy your car though. Kia make great EVs. I have the Soul EV. Just don't get to drive it enough right now.