Although not AUDIOFOOL quality, and no magic about them, I have used Dayton Audio BR-1's in my little digital production studio for years, and I have no need to upgrade them. They use a neat little 6 1/2 inch woofer that goes down to about 40Hz, and they have a real solid low end. Available as a kit, for about $150.00 (that's dollars, not pounds). Can't get anything better at that price, unless you can score something off Ebay. There are some modifications available on the 'net which are stated to provide improvements, but I have not done the 'net mods. My crossover network uses stock component values.
And good luck from that (bass) reflexive old guy,