Not actually specific to you Mau, my friend, but...This is getting weird as they did not give the wrong time at all, 6pm GMT is correct as we Brits, even after we have made the Daylight Saving Time adjustment, still use GMT because, effectively it still is to us.
We do not walk around saying "Hey my watch says it's 5pm, but you know really...it's only 4pm!" There is not one British person that would read 6pm GMT and assume that the DST adjustment was not already accounted for. I know that there are other DST shifts in the world, that the UK is not alone...so I am confused as to why this has really seemed to have become an issue.