I mean, if anyone on here doesn't know that by now... Mullard hasnt made the guitar tubes we want since like EL34s in almost 4 decades, and hasn't made ANY UK tubes at all in 2 decades.
It's just a rehashed branding from EHX/New Sensor like most others, usually with an attempt to replicate the physical characteristics of the original mfg. to some degree possible using newer equipment.