How can you say it won’t need a rewire?It is wired in PVCcables with RCD(?) protection for the whole installation, get it tested by all means, but no need to rewire or replace the consumer unit.
A majority of installations from that era did not have to cater for appliances that are more commonplace these days. As a consequence, it’s quite common to find such installations subject to horrendous DIY additions or modifications.
This installation could well have been compliant with the wiring regulations from fifty years ago but I doubt it would pass an inspection as satisfactory which could cause problems later on.
Advocating that electrical installations don’t need to comply with the current wiring regulations might be considered as unwise guidance with consideration to the improvements in electrical safety made over the last fifty years.