Getting compression working 100% with BT seems to be an absolute impossibility.
For webpages with a .php extension you can get it partially working by adding the following code to the top of you page and it will compress your .php files, at least:
ob_start("ob_gzhandler");
(it needs to be inside a PHP code block but the forum here wouldn't allow me to post it with that)
Anyway's, it's far from perfect because the .js and .css files still aren't compressed.
Personally, I have been round-and-round in circles on this with BT and I can't find any solution. I was told "you can't use GZip" and then "you can use DEFLATE but not GZip" and then "you can use GZip but not DEFLATE". I have tried what BT support suggested during all that, and I have also followed every credible example I can find online, including Google's advice (which is undoubtably flawless)... Nothing works... I feel inclined to move towards a different hosting company -- it is pretty standard now and most hosting companies offer the ability to do this, BT are just being stubborn, that's my conclusion.
How many of y'all are also finding this?
Maybe we can create a petition to push BT to do something about it?
P.s. Not that it will help, but Google advise looking at these:
http://httpd.apache.org/docs/current/mod/mod_deflate.html
https://github.com/h5bp/server-configs
