Deep nights are really tough I must admit but then again waking up at 03:30-4:00 AM on a week of early's is a killer too..Im not sure which one is worse ha... The Royal Mail routes are easy though, the latest finish is around 02:00 UK local time and most are just two short sectors..
These days whether its Low cost, night freight or long haul, they're all knackering unfortunately...
Regarding First Officers basic salary, its £33,458 for an FO and £38,630 for a Senior FO
Senior FO = 500 hours on type or 2 years in the company, which ever comes first