Struggling with transitioning back to the office

I have a 9 month old Cavapoo, which thanks to my job, I've been able to raise whilst working from home. I knew that I would eventually have to go back to the office, and as a result have spent lots of time training for this. This includes crate training, leaving the home progressively longer (e.g. 30 seconds, then getting mail, shops, gym, work inspections, few hours etc).

Everything seems to be going very well, and he seemed to be coping fine. No signs of separation anxiety at all. About 2 weeks ago I have started to transition back to the office. I leave by about 8am and arrive home around 4pm. He's been home longer than that before (not in a crate, free roaming limited to our living area + balcony only).

I don't work in the office every day, maybe 3 days a week now.

We upgraded our camera recently which better tracks noises (like barking howling etc). I have since noticed, now, that at some point during the day our puppy starts to howl (like a sad howl), which seems to be new (though potentially maybe the old camera wasn't good enough).

The howling is sporadic, and does not come with any other bad habits (no toileting inside, not chewing / destroying anything). A review of the camera shows this:

• We leave the home in the morning. Maybe a little whimper for 30s.
• At some point in the day he'll howl (could be 1hr after we leave, could be 2, sometimes even 5-6hrs).
• Howling is in short bursts (maybe 3 howls 30s apart). Then usually lies back down and sleep. It may be another hour for the next howl, sometimes 5 mins apart, or 15, 30 etc.
• He always lies by the front door of our apartment, though does this when home also, as he likes the breeze and also hear out for the neighbours in our stairwell.
• The other day, he didn't start howling until 3:30pm, then thereafter it was ever 10 minutes.

I really don't know what to do at this stage, and want to make sure I don't make it better or worse. I've read so much conflicting info online as well.

I think he is currently going through a "secondary fear imprint stage" as things recently (even before going back to the office) have scared him, like bikes, people approaching at walks etc.

I don't think (?) that it's separation anxiety as he doesn't seem to be ever really panicking. He'll just walk around the unit, sit up on the couch, or sit by the door, and howl. Occasionally he'll try and get something up from the table or something. Never any mess, destruction, etc, most of the time he's sleeping.

I guess my questions are:

• Is this just him readjusting / going through his second fear stage and not sep anxiety?
• He goes for little walks in the morning. Should they be longer?
• Would TV / Radio / White Noise during the day (can set timers) help.
• I can't really go back home to work any more, though would restricting hours help (e.g. return at midday instead of 3pm or something).
• Arrange for dog walkers at 11am or midday? Or would that train bad habits.
• Doggy daycare where I live would send me broke, though could do a day or so to help?
• When working from home, try and have more separation to limit him being as clingy.

• I could potentially take him to the office, but that doesn't seem to be helping the issue.

  If anyone has any advice, words of reassurance, etc, that would be great.