> the only problem is most car drivers won’t expect you to be going so fast.

Not the only problem - if you get caught there's also possible prosecution, points on your driving license etc. What's doubly annoying is that even if you want to do the right thing and register your 1000w e-bike as a moped there are still barriers in the way, e.g. finding insurance, getting it MOT-d. Still another issue is that once it's registered as a moped it cannot be used on cycle paths etc. It really is ridiculous at present and the law needs updating.