Where can I find glide ratios for commercial aircraft?
The glide ratio is closely related to the lift/drag ratio; as lift/drag ratio is closely related to aerodynamic performance, aircraft manufacturers are very restrictive on such data and little reliable information is publicly available. 
Some guesses can be made from incidences like Air Transat Flight 236. For the A330 this results somewhere around 24.

I'm not aware of any data on BA146/RJ85. As BA146/RJ85 focusses on short haul it may have a slightly lower glide ratio; 4 engines are also not favourable for a sailing plane. Still anything below 20 would be a surprise to me.



Edit: Seems I sort of mixed up the numbers. The A330 should be somewhere over 20 (quite a time since I worked on that...). Fopr the RJ85 on this forum the glide ratio is estimated as 15:1. 

P.S.: Keep in mind that all these values are maximum values that can be reached under optimal conditions. Real values may be lower.