5.3 The distance of all races, from the start signal referred to in Article 38.11 to the chequered flag, shall be
equal to the least number of complete laps which exceed a distance of 305 km (Monaco 260km). However,
should two hours elapse before the scheduled race distance is completed, the leader will be shown the
chequered flag when he crosses the control line (the Line) at the end of the lap during which the two hour
period ended. However, should the race be suspended (see Article 41) the length of the suspension will be
added to this period.
I think that clears up the time thing for me, but its still a little confusing.
To me, that says 2hrs
plus 25 minutes - the length of the suspension - assuming the race was stopped about 1310BST, and restarted (behind SC) at 1335.
This would then mean the race would have to end at 1525BST. Now you mention this, it makes sense of what Martin Brundle said - they were talking about the two hour rule and Martin mentioned that they finish in about "X" minutes - about 15 minutes before they'd stop the race for time. The race finished about 1510 - 15 minutes
before 1525, so this makes sense.