The Mitre has an established boozeratti who have little interest in new fangled shenanigans such as seasonal beers. So, yes .... the Old may be a little too old.
Personally I only drink Harvey's Old in Eastbourne at The Lamb or The Victoria.
Longman Sussex Best is a cracking pint and it's 20 odd quid cheaper for a nine and more consistent in quality.
At it's 'best' Harvey's gets the nod for me but there are very few places I will drink it.
Namely:
Poet's Corner, Mitre and where I work.