A basic reference (or factual reference) is a short summary of your employment. For example, your job title and the dates you worked there.
https://www.acas.org.uk/providing-a-job-reference/what-emplo...

So they err on the side of caution and provide a standard reference that confirms employment and dates worked only.
https://energyresourcing.com/blog/references-more-important-...

Reference requests for current or past employees will normally be handled by
Human Resources (HR) and it will be Monitor’s practice to provide a standard letter containing factual information as set out in the attached Appendix A.

Dear NAME
EMPLOYMENT REFERENCE FOR STAFF NAME
Thank you for your recent letter concerning STAFF NAME.
I am pleased to confirm details of employment with us as below:
Job Title: ROLE
Start Date: DATE
Leaving Date: DATE
We have no reason to doubt their honesty or integrity.
Please note it is our policy to only provide this basic information for employment reference purposes.
In accordance with Monitor's normal practice this reference is given in good faith and in confidence, without legal liability on behalf of the author or Monitor.

Yours sincerely
Director of Human Resources & Corporate Services



https://assets.publishing.service.gov.uk/government/uploads/...