They are out and about day and late into the evenings, farthest West I saw or rather heard them was St Davids West Wales returned to Mildenhall via Cardiff around 23:00 lowish could only see the nav lights but sound they make was unmistakable. If you go here
https://tar1090.adsbexchange.com/?icao=c0607d
Click the 'U' button top right on map it will delete all the civil stuff from the map leaving all the military traffic to view, the Ospreys seem to use KNIFE callsigns but their icon on screen is again unmistakable with the twin props. Quite surprising how much military activity is going on, lot of air to air refueling and AWACS activity over the North Sea daily. C17 traffic to and from Cyprus, USAF C17's to and from the States and the list just goes on with all the training and front line stuff up there.