I notice that some of the Wylfa Newydd RRs are over 500 words - is this not a hard limit?

Advice Note 8.2: How to register to participate in an Examination (attachment 1) states on page 3 that:
There is no word limit on how much to include in your Relevant Representation; however, the Examining Authority may only have a short period of time to read all the Relevant Representations before the Preliminary Meeting. As such, you should make sure your main points are clearly set out. We recommend the use of bullet points and headings to highlight your main points.
While information on the online registration form states:
Here you must provide an outline of the main points you intend to make in relation to the application. Failure to provide this will mean that we are unable to register you as an Interested Party. Please aim to limit this section to no more than 500 words.
Taking this information in to consideration, there is no maximum word limit; however we encourage parties to provide a concise summary of their opinions.