Thanks to all, very helpful replies.

I've narrowed it down to either the Sony WH-1000XM3, or Shure SE215 with Dragonfly Red/Cobalt (Richer Sounds do very good value bundle deals for those).

I did just think of a potential stumbling block with either, though, using Roon, in that I was intending to apply a little EQ, as I do with my HD650s in Roon to tame the worst of any frequency anomalies. All fine when I'm at home, but of course these will be work 'phones and I do work out and about with the laptop - which begs the question of how to use Roon in such a scenario.

I can store some files I want to play out and about locally on the Macbook, but is there a way to switch cores 'on the fly' as it were?

If not, I can happily use Tidal with locally stored files on the Macbook/iPhone, but is there a suitable EQ app for either in conjunction with Tidal...?

HC: 861v4/ID40/LPS, DSP5000, DSP5000VC, DSP3100, SW1600, HD621, Oppo BDP-105, Sony VPL-HW55ES
2-Channel: TEAC VRDS-7/Trichord Clock 3/PSU, Avondale S100, Harbeth Compact 7ES-3
Previous Meridian: 5000C, 5200, 7200.2, 6000, 562V.2, 568.2mm, 800v4, 808.2i, 818v2/v3, 861v8, 551, 502