Gatwick Twilight Checkin

Hello all, I'm hoping someone may be able to help me regarding the twilight checkin at Gatwick.
I notice there is a 6Kg (I think) weight limit on hand luggage, do we need to take this with us to check in the evening before? Or will they check and weigh the hand luggage before we board the plane the next day?
Never done the Twilight before and don't want to turn up on the morning of the flight and have to start messing about with luggage.
I know the simple solution would be not to pack as much in the hand luggage but we never end up travelling light and use as much space as we can when we go away!!
Many thanks,
Olly.
I notice there is a 6Kg (I think) weight limit on hand luggage, do we need to take this with us to check in the evening before? Or will they check and weigh the hand luggage before we board the plane the next day?
Never done the Twilight before and don't want to turn up on the morning of the flight and have to start messing about with luggage.
I know the simple solution would be not to pack as much in the hand luggage but we never end up travelling light and use as much space as we can when we go away!!
Many thanks,
Olly.