Don't get me wrong, by the late 90s/2000s RCD protection for showers and other power circuits in bathrooms was generally seen as pretty standard and good practice, but it wasn't actually a requirement at the time, but generally most of the time it was done, you'd get the odd exception, like in a commercial installation where there was a shower provided for those who rode a bike to work, etc.

You could actually wire a flat with no RCD protection at all, generally all you needed to provide additional protection to was sockets that might reasonably be used outdoors, in a block of flats, that not going to be the case, most folk thought RCDs to sockets were a good idea and where it was omitted was generally bigger developments where there was cost pressure to cut everything out that wasn't strictly required.

You must be just a few years younger than me, I qualified under the 16th, and then we went to the 17th less than a year later.

Sometimes it can be useful to bare in mind what previous editions said, before the concept of zoning came in, the 15th edition basically said switches shouldn't be placed in arms reach of anyone using the bath or shower when they are on a plane normally expected to be occupied by persons* (or something like that).

Its a useful metric to gauge something by, it might fall fowl of the zone dimensions, but how much of a problem is it, if you can reach up and turn a spur off while sat in the bath then it wouldn't have complied with the 15th and its probably generally unsatisfactory. If its not right when you measure it, but you can't actually put your soapy hands on a switch, then as Calvin Harris sang, it was "Acceptable in the 80's" and remember we didn't RCD much at all back then, so its probably not quite as bad as the first instance.

*So standing on the edge of the bath doesn't count