So I've gone back to the original risk assessment I started before taking the forum offline and completed it. I think I've worked it out now.
That Online Assessment tool has a record keeping downloadable file. Where you fill in all the information for the 17 illegal harms - coresponding to what you filled in on the online assessment tool. You then get to the section in the online tool for recommended safety measures and copy those and their "codes" into the boxes at the end of the downloadable form.
That completes all the record keeping and risk assessment (I think). It's intended to be emailed back when completed (ie recorded and reported) but I didn't email it back because I think smaller sites don't have to.
So going through all the recommended safety measures, you copy each one, one at a time into the relevant box (they are small one line boxes but expand so you can add all the measures one by one).
So for example this recommended measure for "Content Moderation Function".
You put
ICU C1 Content moderation function to review and assess suspected illegal content
in the box
Next box you put when it was implemented (date)
Then you add the "relevant codes and duties" (copying and pasting them) - in the boxes for those. See screenshot below.
So the relevant codes for that measure are
Relevant codes: Child sexual exploitation and abuse, Terrorism, Other duties
The relevant duties for that measure are
Relevant duties: Section 10(2) and(3). Section 21(2)(b) Online Safety Act 2023
So I've finally got it completed. Just using the online tool and the downloadable form (but it's not a pleasant form to fill in and saves as some kind of word document that has extra functions, so it can't be linked anywhere as a word document). EDIT: It's an ODT document. So now saved it as a word document and it's a normal Word Document now.
This is what mine looks like in the end section (after completing all the individual online harms and risk factors and mitigations etc).
Apologies if people already know all this and I've only just fully worked it out. And there are probably other ways of doing record keeping and risk assessment as well.
Basically, by going through the online tool step by step, it gives you all the information needed to complete the record keeping and risk assessment. Your low risk, negligible risk selections on the online tool, need to tally with what you then record on the form. Adding your specific risks in words (or lack of them) and what is in place to mitigate them. Then state what evidence there is of that (I just stated screenshots of software like CSAM from cloudflare, spam settings etc as evidence and other software used).
The final bit of the online tool - recommended measures. Gives you all the measures for your circumstances (having completed the earlier part of the tool), which you then copy and paste into the relevant boxes (as above).
If doing it again next year, on review, I think I'd just type it as a word document, but completing the form was useful to know exactly what was needed for the record keeping and risk assessment. Horrible form to fill in though.'
I hope it isn't a similar lengthy process for a Child Risk Assessment, when it gets published.