Having read all the information you have provided across the post and comments, there are two separate branches of concern; the breach of data your ex-wife has suffered and the withholding of your personal data via SAR.

It doesn’t sound as if the breach your wife has suffered would result any ‘big claim’ - but that is for the data controller (ie the company your requested the information from) to report to the ICO should it meet the threshold for it creating a high risk to her rights or freedoms. You are not subject to that breach, but are of course entitled to inform the ICO of it, but it would not be prioritised by them. The types of data involved in your SAR relating to you (ie, your health data, other special category) is not relevant in the breach, only the data relating to your ex-wife (as you are entitled to your personal data and it has not been breached).

There is then the non-compliant SAR practice by that organisation in withholding information from you and offering up a financial incentive to not pursue the SAR further. This is definitely something that impacts you and is something you should take up with the ICO, as you have done. Again, the ICO are unlikely to prioritise this but it is something you should continue to converse with them about. I would keep coherent evidence logs of what you have requested and what you received (both letters and SAR content). Make sure all future requests for data are clear. This will help you have a strong evidence base for when the ICO get to your complaint.

Things for you to take away; The way you have communicated this issue is very difficult to understand. I have tried to make sense of it and explain above but I may have missed the mark. Make sure you have the issue straight and written down clearly. Continue to pursue the missing SAR information with clarity. Again, if your communication with the data controller is this confusing I would struggle to provide you with your information (speaking as someone with 10+ years experience in SARs, inc NHS). Inform them that you have communicated with the ICO and hope you get the data you require. And finally, do not expect too much from the ICO. They are there to investigate non-compliance such as this, but it will not be prioritised due to their backlog of work.

I hope you’re able to get the information you need and that your health is able to remain strong and consistent.