I basically lived in this last winter while working from home. Pair of merino long johns under trousers and plenty comfortable for work! No way I'm heating the house all day this winter, will just have it on in the evenings.
Shroud Hooded Men's Jacket | Mountain Equipment
Densely knitted high loft Cycloknit fabric is combined with lighter and lower bulk Pontetorto® Tecnostretch fleece inserts to make this an exceptionally warm technical layer. Sufficiently windproof to be worn alone in better conditions it’s also a formidable mid-layer under a shell in severe...www.mountain-equipment.co.uk
I have a similar item that I term my 'all weather' jacket.
Its a mid later and its good in temps down to single figures up to 20c
Basically my go to. Its so comfy. I live in it in winter.
You can get some lovely, comfy 'cool to cold' weather gear that isn't size of a huge jacket.