Did you adopt your pup here in HK? We are in the same boat, so to speak, at the moment.My husband and I adopted a 1 yr old beagle from a shelter ( originally passed off as a 7 mth old pup, but I saw through that and realised that this was a dog that wanted to be really, honestly loved without obligations
!) recently, and he has serious separation issues since adoption. For a dog that has lived his first year in a cage unless to sow his royal balls off, he started out as calm, ok, active for his breed and age but it has become worse given that my husband works from home when he is not travelling and spoils the dog...And no, we do not have a helper.
I do suggest a dog walker coming into your home at least twice a day, plus plug in a couple of vials of Feliway ( available from your vet) into your walls to keep him calm ( even catnip may help - ours made a hell of a lot of mess but we came home to an unusually calm beagle - he actually stole the cat's supply. Cost the poor pup a few swipes of the paw) . Also avoid cooked bones but buy your dog a raw bone from your butcher to gnaw on during the day as a reward and to keep those jaws busy. A clean comfy bed ( ours ate the lovely new one we bought him by the second day) with lots of chew toys to relax in. You can give the pup a small snack before you leave. Yes, new age music like Secret Garden does help - our cat prefers Richard Clayderman. Dog prefers TV. Plenty of options. Working long hours and keeping your dog cooped up in a small apartment is not fair but if you spend lots an lots of time with them when you are home that would help alleviate their separation anxiety.