Hmm
I was told about 2 2 speeds. One on the emtor one on the front by the nozzle. I guess putting Kirby in portable mode activated switch. The other was was using hose on exhaust or something to do with emtor.
I would not mess with it. My g7d runs fine. It's had a tune-up from vacuum shop. I wouldn't say it's an issue if you use your vacuum normal you won't have issues.
I know it's got two speeds in two different places. I have not heard of the issue and being your in the UK I think the motors already in high speed with higher voltage.
I say don't fix something that is not broke.
Enjoy it as it's from what I have seen the most like g series Kirby.
Les