A recent topic on the mk 3 Forum raised the issue of tyres over 10 years old. Which may apply to some low mileage owners. Including the spare tyre.
This a UK MOT fail but only on cars with 8 or more seats. (presumably fewer deaths than this is considered acceptable if a tyre blows out on the motorway

)
I Attach a screen shot from the mot testers manual, including how to read the date code on tyres (sometimes this code is only on one tyre wall - possibly the less visible inner wall ,but worth the extra effort of checking, IMO. )