I have got a front scrub (metzeler Racetec) that I bought about a year ago and it has been outside ever since, including the cold snap this winter, would this affect the tyre in any way?
I believe it was Bob @ FWR that told me he used to use old tyres for practice sessions when racing his GSX-R 1000 to the win of the British Superstock championship.
This was when I was worried about using an old Pirelli Dragon Evo on my R1 at a Cadwell track day that was at least 5 years old.
I believe as long as a tyre is stored in a cool environment out of direct sunlight, it can be stored for years.
You can find the date of manufacture in weeks as a number on the sidewall.
In your case, not sure. Wouldn’t use it on a track day 
Check this Bridgestone guide
We used to have a very good independent tyre dealer near me who avoided holding any obscure stock because of the shelf life.
If a tyre got to 4/5 years old he’d sell it at massive discount if you signed a warranty waiver. At five+ years he’d give them away and just charge for fitting and balancing and you got a receipt for only that service. At 6 years, he’d scrap them.
All his tyres were dry stored on racks in a windowless building. Sounds like he new what he was doing.
HUmmm, so I seem to be OK on the age front, but maybe the storage conditions were not ideal, most of that time was in a shed out of direct sunlight, but the past few months were on a balcony which gets the sun in the evening…I’ll show bob and see what he says…