It’s certainly an impressive padlock!
Not one I recognise though- I wouldn’t rule out Chubb as it does look similar to some of theirs, but one thing I’ve found with most special application locks they made was they were usually marked with their name. They were of course one of the more well known makers by Royal Appointment, and made all types of locks including unique ones for Goverment/Military briefcases and even Gladstone (doctors) bags etc.
The padlock looks to be all brass from the pictures- shackle brass as well. This combined with the Arrow marks indicates probable military use- possibly for explosives, storage chests, magazines etc as the use of brass eliminates the risk of sparks. Or, it could be from Admiralty/Navy use- again brass being favoured for marine applications and it’s corrosion resistance.
I’m sure someone will recognise it and be able to identify it for you!