Probably somewhere very non-descript in a flat/bedsit that has at least two different exits in a building that also has at least two means of escape and private access to a flat roof that adjoins neighbouring flat rooves/fire escapes etc.
Loud hi-fis/AV systems and even earphones are out because the noise would enable people to get in/break in to the building unheard. (He would also need to be aware of the routine habits and comings-and-goings of other residents so unusual patterns of activity could be detected immediately.)
So far as other people are concerned, he needs to be as 'invisible' as is practically possible. Cheap clothes and accessories that don't raise any eyebrows and nothing in his living space (like megabucks furnishings and gadgets) that would tip off a nosy landlord or neighbours, meter-readers etc. that some kind of 'double life' is going on.
Ever changing girlfriends would be a no-no (at least not in the flat) unless he was living with a female colleague who was in on the cover.
The car would need to be as non-descript and bland as his appearance. (10 year-old Astra or similar.) He would need to seem a quiet, brusque, unsociable so-and-so to all of his neighbours, so that they are never tempted to approach him sociably whether indoors or out.