I teach at a university (design students, so not coders and probably only a year or so older - so i think a computing student would be way ahead at a A-level!)
I've been teaching Javascript mostly as its easy and useful if you want to share a project online of course. This may not be what you're looking for, but its a web development alternative:
I've been using p5js (JavaScript implementation of Processing and very well supported by a channel called the Coding Train on youtube and here:
https://thecodingtrain.com/)
Their online editor enables you to code without downloading anything and will work on practically any device bigger than a phone, which makes it fun to teach. I made a weather API example here from a Coding Train tutorial to help a student recently:
This is taken from a video from the Coding Train youtube channel: //
https://www.youtube.com/watch?v=ecT42O6I_WI
The API i used was not the Met Office's API to be honest as its not that easy to use, i've a post elsewhere about this, but a big issues is that its endpoint isn't https so you get errors with any modern https web page! For teaching purposes (and many others) tool like this:
https://openweathermap.org/ are pretty easy to use and give you decent data. Depends what you want to do of course and if it needs to be python then it should still be useable.