Is there any information or ACPs on playing a bugle or some sort of instrument when lowering or hoisting the squadron ensign on parade? And rules/ regulations
No rules to say music is to be played etc. Bear in mind on RAF Stations, you only have the whistle blows before and after it is raised/lowered.
The lowering is to be done slowly and relevantly an example with an instrument is available here
The main problem I see with music is the tendency to slow the proceedings to match a particular piece, rather than simply playing a tune over the time it takes to normally hoist or haul down the ensign. It holds people up unnecessarily.