Where would you start
For the UK
I would include a massive chunk of the back catalogue of On U Sound, Ariwa & Pressure Sounds.
For earlier reggae, Magnet and Trojan are chocka-block full of UK classics.
In my house, Misty in Roots Live at the Counter Eurovision is the 'Its Alive' of British roots Reggae.
For current UK greats I'd put Ricky Ranking up there.