The entrance is round the back and the door is a covered by a kind of porch/smoking shelter, so it's fairly discreet. Once you've been buzzed in you'll find yourself in a 'reception'/waiting area, which is basically the kitchen of a hollowed-out terraced house. You'll probably have your temperature taken and be asked to use hand gel - at least I was post Lockdown 1.0
There's a free car park just over the way from the entrance and usually plenty of adjacent street parking available. From the front, on the main road, it just looks like a normal terraced house. On a previous visit of mine, some people were working on a car near the back entrance, but the receptionist told me it was only the next door neighbours, and they're ok with what goes on at Roses.