The Canadian CC-130 & the US C-40 are flying in an airway.
Think of it as a highway in the sky.
It is like a truck & a SUV maintaining formation on the road.
Sometimes planes can be very tricksy to track so you can use the second one of the pair as a rough guide to the location of the one that plays hard to get.
Looks like fairly normal night flying training. Area to the south of Swindon is Salisbury plain a large military training area.
Helos further west are around Yeovilton home to much of the Royal Navy Fleet Air Arm assests.
G-FRAU is a training support aircraft operated by Cobham a civilian company that provides pay for use training facility.
SHF481 Chinook is from the RAF support helicopter force based SW of London at Odiham.
I have a Brit army Defender AL2 a little off his patch flying over the Western Isles. Usually he is seen operating over Northern Ireland.
It might be a training flight but something tells me he is checking something out.
This aircraft has a pretty comprehensive recce fit.