Sorry, I forgot that there's an extra step for wills issued before 31/12/95.
Look below where it says '0 results returned', to where it (hopefully) says '1 document page returned'. (There might be more than 1 page if it's a common name that you're searching for). Click on 'Click to Open Image and Order Document Form'.
Look through the information on that page to locate the person whose will you're seeking. Then carefully transcribe the information shown there into the righthand panel before clicking 'Add to basket'.
Note that that system only works where probate was sought in England or Wales. For Scotland, see here
https://www.nrscotland.gov.uk/research/guides/wills-and-testaments
For Northern Ireland, start here:
https://www.nidirect.gov.uk/campaigns/public-record-office-northern-ireland-proni
If probate was sought overseas though, you might need to contact the relevant embassy, to enquire as to if/how the will can be retrieved.