Is there a way to watch a continuous stream of all Doppler Radar footage from the 1990s to now?

Damn that would be interesting

Theoretically, yes, but you might have to go through the CEDA archive to get it all (i.e. sign up to CEDA, then make a data request).

Chilbolton observatory have live data feeds which I like, but they're RHI not PPI so maybe not what you want anyway.