Another benefit of adding a BF midget is that this effectively gives you [b]three[/b] rigs:
Amp + Midget = tiny but surprisingly big-sounding rig - I also use this as my practice set-up
Amp + Compact = what you have now, and what I use for function band gigs
Amp + Compact + Midget = take no prisoners - I use this for loud rock gigs
Of course if you then get another (spare) head, you have the same all over again in a different flavour, plus you can have two complete amps set up for teaching (if that's your thang).
At the risk of stating the obvious, don't just add any other 8ohm cab to your Compact, as they are not likely to play together nicely, let alone look bitchin'!
Finally, if you are anywhere near Swindon, PM me to try your bass guitar and amp head through various Midget/Compact combinations. I can even play guitar while you do this to give you an idea how it would all sound in a band context.
Oops - have I stoked your gas!?
[font=comic sans ms,cursive][i]PS - I am not looking to sell any part of my bass rig.[/i][/font]