You're not going to like what I'm about to say, but if I were you, then I would be to forget any advice that you might receive on implementation of REACH that you receive from an internet forum. I'm not suggesting that SJB's advice is bad (it's not, it's good advice obviously), but I suspect that you are more specifically concerned about ensuring that you meet any obligations (registration/notifications etc.) under REACH legislation and need to get it right.
REACH is a potential minefield. Given that you described your intermediate as 'on-site isolated', you have clearly done your homework and are already familiar with article 17 and are most probably producing less than 1 tonne of intermediate per annum otherwise the question is somewhat moot! I'm guessing that the question you are asking boils down to whether or not there are any other obligations which may be relevant to your circumstances. The link below is perhaps a good starting point to help address this question and includes a navigator tool which might be helpful.https://echa.europa.eu/support/guidance-on-reach-and-clp-implementation/identify-your-obligations
If you're still confused (and who wouldn't be!), then get in contact with an expert. Most countries have help desks who are able to provide advice and support. These guys are far more qualified to give advice than I am and have a vested interest in you getting it right... At least by contacting them you can have some certainty. https://echa.europa.eu/support/helpdesks
Sorry to be a bit vague, but understandably, I don't like giving advice on matters of law.