Is this surprising? We've heard over past few weeks especially that viruses mutate 100s and 1000s of times and this was almost to be expected.
I guess it's good they've quarantined 2 cases and contacts so far and we just have to hope there's no further cases found.
I am surprised more areas aren't in Tier 4 though. Still remains in London, South East and now covers more surrounding areas i.e. Sussex, Oxfordshire, Cambridgeshire, Essex, Norfolk. Thought it'd go further west and towards the Midlands too.