Either I have REALLY Low standards, (probably) or Maybe I don't understand something here. So take this with a grain of salt.
Have you looked for Used Car Audio subwoofers? I know DUAL is sold in the UK. And so is Infinity. There is a $98 Buck Bass Tube that would would rock your socks off in a home. Power can be had from an Old receiver.
I get its not Posh, but... I don't see why you could not get a great subwoofer(s) for $200 bucks all powered.
I don't want to make it more complicated than it needs to be. Or discount the turn key approach to home subwoofers. But if I had to do it? I would do Infinite baffle in a home setup. And then use some Cheap Rockville Pro woofers. (2 for $50 bucks it use to be)
If you are ABLE to find some deals and willing to go to Ikea to the As is section, those LARGE Kitchen Cabinets that have Solid MDF on the sides would make a great Table subwoofer that would look nice, and have ZERO issues playing down to 25Hz or lower (Long SonoTube) Even the Cheapo AutoTek Woofers ($25 bucks) in a sealed box not only sound great, but they are actually quite good at even classical music in a sealed box. And I PUNISH these woofers. (see my driving Playlist recommendations)
Also,
with a Sonotube subwoofer, you don't get Bass loading. so you don't get that Boomy sound. It's more natural and does not load the room like a sealed subwoofer would do. For that Budget Champion? The DUAL or the Hifonix Subwoofers work AMAZING in the home. 4 of them will give you such low extension in your music, and yes. Tested them if they integrate with my Magnepans. They work great to my ears. But take that with a grain of salt. Look at the music I like to listen too.
BTW Infinity is clearing out their Primus line of Car audio 12" Subwoofers for less then $40 bucks each.
If you want a BIG powered subwoofer for MUSIC? And Active? Well, amazon, if it works the same here in the USA? They let you order and try out stuff and return them if they don't work. So... How about 109 Pounds for a Powered 15" subwoofer? If you just want turn key. Might have to use an adaptor for the input, but for the cost? Chances are its going to get the Job done. Might not do Hair tricks, but it will get the girls rocking if you have a Party.
https://www.amazon.co.uk/Evolution-...97134&pd_rd_wg=dqvHq&pd_rd_i=B00YHJEQP0&psc=1
If I'm on the wrong track, then sorry. Carry on.