DCIS - Shielding letter today very confused

Hello there I’m new here, wasn’t sure where to post so I hope this is appropriate.

I was treated with surgery for DCIS Sept 2019. Histology and surgical factors were favourable so I elected not to have radiotherapy - decision supported by oncologist & surgeon. I had chemo for a different cancer 20 years ago, otherwise healthy and active. Because of 2x cancer diagnoses have been referred to clinical genetics but not been tested yet. Have certainly not been thinking I was extremely vulnerable re Covid-19 as I had no radio or chemotherapy for recent DCIS. Then today I got the shielding letter from Department of Health - and a call from my local council as I am apparently on their vulnerable spreadsheet. I have heard that the letters are generated by algorithm and can be wrong - but since I am not on active treatment I really can’t understand why I’ve ended up on the list (and this is the first letter I have had). Phoned hospital and advised by breastcare nurse that they wouldn’t advise me to shield, but GP surgery said they didn’t think it was a mistake - but not spoken to GP yet and confused about what they are telling me. 

Very confused, any advice welcome! Thank you

Hi - I’ve read quite a few similar posts with it making very little sense why you would be asked to sheild and vice verse people who have been told by Consultant they should shield but didn’t receive a letter .I will try and copy you a link to BCN advice about this .Unless you have other health issues I can’t see why you would be asked to shield x