A decent car or racing bucket seat certainly has potential, but you would need to buy or build a frame for the wheel & pedals etc. For simplicity, Currys offer this among other options: https://www.currys.co.uk/gbuk/gamin...7-gaming-chair-black-orange-10164407-pdt.html
There’s an unused one on FB marketplace in Cambridge for £80. It scores 7.9/10 across 230 reviews, so it should be reasonable and might do the job with less hassle if you can find something similar near to you.
Christ, end of thread! So the purpose built, unused, as new, ready to go solution is £80, when a car seat is going to be £50 all day long and you have to build a load more stuff and make it work? Get to Cambridge. As ever, don't build it if you can buy it.
That is of course unless you want to build this together, as an activity, offering education, teamwork, father/son bonding, etc, in which case you have a reason to build it and not buy it.