Hello Shane.
Can’t stay away from this, it is clearly a bug to shove the seconds into some construed timezone, if Coventry had its own timezone, it should have been listed as UTC -00:06:00, with offset to GMT. Honestly, I’ve been giving this just a quick glance, but to me it seems like it has given the offset with respect to the Coventry timezone, which is nothing anybody would suspect really, since timezones offsets, at least as I have seen them, are written relative to the Greenwhich Meredian, or what it is called, when we are dealing with UTC.
Time travelling seems like hard work, still, I think London can take it. 
Big Ben, is soon to be baptized the Elizabethian Tower or something, isn’t it, but then again, Big Ben is allways right. 
Coventry is 1.5 degrees west of London, therefore it’s longitudinal coordinate is -1.5. Now, the Earth travels around the Sun with a velocity of 24 hours per revolution, which means that it uses 4 minutes on rotating one degree. (15 degrees per hour), this leaves Coventry 6 minutes after London, hence UTC -00:06:00.
Thank you Shane, it feels comforting to know where the seconds went. 