World Time Zone says that it's 5 hours difference between Mudcat time (Eastern Daylight Savings) and GMT (Greenwich Mean Time), but it's only 4 hours difference between Mudcat time and Reykjavik, IS. 7PM (1900) here is 11PM (2300) in Reykjavik.

Also here is a time converter with a map of time zones: World Time Table

Not knowing who does the clocks forward and clock back thing, I'd say the easiest thing is to figure out your time zone's difference from GMT. (The map I posted the link to says the UK is on GMT, but I don't think that's true?) The show comes on at midnight, GMT.