Heh!
a) Warhound is spot on. We tried extensively to level bomb at height in the Blenheim but found other problems in addition to the control issue, such as lack of forward view to track correctly, and needing to input Indicated airspeed rather than True airspeed/groundspeed.
Here's the link to the thread;
http://forum.1cpublishing.eu/showthread.php?t=28667
Here's a little vid;
b) Once the port engine is running, press ctrl/o to raise the turret. The left and right cursor arrows turn the turret, your mouse controls the gun, right click and wait a few seconds to reload.
c) after bailing out on the server, press alt/f2 for an external view. Don't use this whilst flying because you can't get back in again.
d) Once you see the message 'Redroach has landed/returned to base', you only have a limited time to taxi. If you keep moving after landing you'll taxi ok, but as soon as you actually stop, the time limit will kick in.
I'll see if I can root out some old vids I did for the first two questions, then edit the post. Bear in mind that the vids were made pre-patch. I haven't assessed bombing accuracy since the patch.
Cheers!