I've now got a full set of vintage Mullards in the preamp section of mine. Sounds glorious!
For those that are interested, from right to left, we have:
V1 = special quality ECC81, labelled M8162/CV4024, from September 1965
V2 = ECC83 from March 1962
V3 = ECC83/CV492 from November 1963
V4 = special quality ECC82, labelled M8136/CV4003, from December 1964