Looking at Sheffield Hallam
https://www.shu.ac.uk/courses/art-and-design/ba-honours-fine-art-with-foundation-year/full-time#:~:text=We%20treat%20the%20foundation%20year,our%20Art%20and%20Design%20degrees.
And their portfolio information
https://www.shu.ac.uk/Visit-us/Selection-events/Portfolio-Reviews-for-Art-and-Design‘The portfolio should include some or all of the following:
A range of drawing skills. Different types of drawing and mark making.
Experiments with a range of media, printmaking, photography.
Typography, illustration, layout, design sheets.
Screen-based/digital work.
3D work and making skills in wood, metal, plastic, ceramic, card, fabric etc.
Sketchbooks demonstrating research, idea generation and problem solving.
Anything else that you feel promotes your creativity.’
https://www.shu.ac.uk/campaigns/guidance-for-applying-to-sheffield-hallam-university-arts-courses/how-to-format-and-submit-your-digital-portfolioI was unable to find information on date so:
I looked at
https://www.ucl.ac.uk/prospective-students/undergraduate/degrees/fine-art-ba#tab1-alevelWhich stated ‘Titles should be included for each image, including the date the work was made, size and materials.’
Then
https://www.ucl.ac.uk/slade/study/ba-bfa-portfolio-guidance/‘General tips:
Focus on key works, it is good practice to start with your strongest work first.
Show your skills and experience of working with different methods and mediums.
Sketchbooks can be presented online by uploading a film of the pages of your sketchbook being turned by hand.
If you are applying straight from school, include work you have made in your own time. We are interested in your interests and passions.
Work does not have to be polished, we are also interested in seeing how you make work, what your processes are and your use of different material and experimentation.
Labelling and annotation:
Title of work
Year and month the work was made
Dimensions
Materials and duration, if relevant
Keep it concise’
So there doesn't seem to be a cut off in that you cannot use old work.
Looked carefully at the universities portfolio guidance, as they may specify a specific file formation (PDF), and file size that cannot be exceeded: for Sheffield Hallam it is 25MB, for UCL it is 5 MB.