I hadn't answered Vincent's question about what data is going to be available and whether is geared for.resources rather than analysis of specific medicines. I gather that the current data is more resources oriented (except for very specific research work) but the replacement system.will be much broader. &ere is an extract from the NHS information on the system, talking about how it is based round records of individuals:
We take our responsibility to safeguard patient data extremely seriously. Data shared by NHS Digital is subject to strict rules around privacy, security and confidentiality and the new service has been designed to the highest standards. 

We do not collect patients’ names or exactly where they live. Any other data that could directly identify someone, for example their NHS number, full postcode and date of birth, is pseudonymised before it leaves their GP practice. This means that this data is replaced with unique codes so patients cannot be directly identified in the data which is shared with us. The data is also securely encrypted.

We would only ever re-identify the data if there was a lawful reason to do so and it would need to be compliant with data protection law. For example, a patient may have agreed to take part in a research project or clinical trial and has already provided consent to their data being shared with the researchers for this purpose. 

So while it will need suitable approvals, it always possible to 're-identify' the data - ie trace it back to an individual. That means we are not just talking about aggregated data - "there were 27 cases of broken shoulders this month" - but are listing all 27 cases, with anonomised ids. The link I gave says almost the entire medical history will be accessible, including all the individual medicines, treatments, etc. The NHS Digital site says it collects

data about diagnoses, symptoms, observations, test results, medications, allergies, immunisations, referrals, recalls and appointments, including information about physical, mental and sexual health

data on sex, ethnicity and sexual orientation

data about staff who have treated patients
It is not entirely clear to me that all these are related to the same anonymised id, though that seems most likely to me.