Thanks for all your comments .... the constructive ones, at least! ;-) 
 
I'm using a MB LMII which, as we all know, has a pretty flat response. 
 
Chris - thanks for the suggestion of the Agi DB's.  For some reason, I hadn't really thought of them.  Will check the DB410 out, but can't remember if it's within my budget. 
 
Thanks again, chaps.