Installing generator transfer switch

[JasperW]

Essentially correct that the generator would have more trouble blowing a fuse (or circuit breaker, what do you actually have?) than the mains in the event of a fault.

I would challenge its statement that "your existing fuse box works fine day-to-day" - we don't care how well it works "day-to-day", we care about how well it works on the rare occasion when something goes wrong. Your non-RCD installation is (probably?) still legal but it's overdue for replacement.

As I said before, getting RCD protection should be a much higher priority for you than worrying about a generator.

I have circuit breakers, I now see that this is a much more involved process than I first thought. Thanks everyone for the input it really has helped with my understanding.

I think my short term plan is to use extensions cables to power essential stuff and lighting in the event of a power cut (which was my original plan). In the spring (when it is warmer and the days are longer) then look at getting an electrician in to inspect the wiring and update the consumer unit, at the same time look at putting a generator switch in.

As you have said it is overdue for replacement!