As you're in the UK you should know better, GCSE's are examinations taken at 15/16 years of age - the level of Electronics taught is absolutely minimal, with the teacher often knowing nothing about Electronics at all.
Generally, a teacher will be appointed to teach Electronics, and sent on a two day course - it could be an English teacher or anybody - and they almost certainly have zero Electronics knowledge previous to this.
So all they are able to do is follow the book exactly as they have been taught on the short course, it's really NOT a very good introduction to Electronics.
At the school where my daughter is now in 6th form, I used to know a guy (called John) who went in as a volunteer to teach Electronics and run clubs - now he was a VERY, VERY clever guy. He worked for Lowe Electronics and (amongst other things) designed their high performance HF band receiver.