Yes, you can certainly demand to see it - as it is your data and you now need to make a Subject Access Request to the NHS Trust which performed the scan.
Here is a useful link for subject access request:
Once you make the request they need to send you the data including the scans within one month. If they do not, you need to report them to the Information Commissioner's Office (the "ICO") who can levy large fines if they find there has been a breach. The fines are either up to £17m or 4% of turnover, whichever is greater. As such, if the scans don't arrive within one monty of your request, I would recommend that you inform the ICO on 0303(###) ###-#### They also have a "live chat" facility on their site - you can visit it here: https://ico.org.uk/make-a-complaint/
They will take your details and if they feel there has been a data breach will contact the NHS Trust and possibly fine them.
If the ICO tells you there has been a GDPR breach then it makes it much easier to claim compensation (under Article 77 of GDPR) - the amount of which varies and depends on the severity of the breach and the impact it has had upon the aggrieved party.
You mention an issue with your GP too. If dissatisfied, patients can complain to the NHS - their GP provider in your case. If dissatisfied with the outcome of the NHS complaint, they can then appeal to the Parliamentary Health & Social Care Ombudsman here: https://www.ombudsman.org.uk/making-complaint
Patients also have the right to compensation where they have been harmed by negligent treatment.
Patients can also exert pressure by referring the matter to their local Healthwatch - who are patient’s consumer champions - yours can be found here: https://www.healthwatch.co.uk ) / to the local press / to your local MP.
If you suspect malpractice, you would also be within your rights to report the doctor to the GMC as a result: 0161(###) ###-####or by emailing *****@******.***