The reason we ask about filing after a wake encounter is that we have to send a form as do both aircraft involved. Its not an MOR but a Wake Vortex Report form.
R/T standards have become very poor over the last year at LHR on both sides of the mic to be honest. Noticed an article in the most recent edition of CHIRP about the very thing. I think that the incident you refer to above about being the last straw was probably a case of being in the wrong place and after so many R/T issues in one session it can be annoying. Especially when Big Airways crews start telling you how to do Heathrow Ground. Its not like we tell them how much flap to select on departure!
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