~12 miles each way. I do 2 or 3 days a week on a good week, 1 or none on a bad week. Takes about 45-50 minutes, would be quicker on open roads, but junctions slow you down.
TBH a few miles shorter would be good. I drive from town to town rather than through the middle of a city so the bike is 30 minutes slower on a low traffic day (a few minutes on 40mph roads, then onto 70mph DC, then a mile of 40mph, then work), through to equal to driving on a catastrophically bad traffic day.
I like it, but it’s a real time sink (15 minutes getting changed/showered at each end, plus an average of 20 minutes added onto each leg of the journey). But then it means I ride a bike during the week, when a MTB ride usually involves loading the car up and driving for 1-3 hours to get somewhere with hills/trails.
EDIT: Daffy, that’s bloody quick!