Just found this service, since I am still displaying my 67 beetles last tax disk before they were phased out.

https://www.creativetaxdiscs.co.uk/ 

They do a nice line in reproduction disks, including slightly aged ones too.

You get control over all aspects of the disk, from date, rubber stamp colour.

My car was registered Jan 1967 so I went for a disk expiring in July 1967 "6 Months" which will also be displayed

Check these out













Take a look, all for around a tenner