Firstly, LNBs aren't that difficult to change, or that expensive, so you're not stuck with the Q wideband LNB. A standard 4-output LNB can be had complete with the fitting attachment for under £15. A hybrid LNB (2 wideband + 4 legacy SkyHD/Freesat outputs) is around £40.
Second, the latest generation (gen-3) Freesat boxes work best with a wideband LNB. You get to record up to 4 channels at once. Going back to a regular LNB means that the same gen 3 box will just let you watch live plus record one ch or record two channels whilst watching a previous recording.
If the thought of changing the LNB is too much to get your head around, there is a device that can take the wideband signal and convert it to the legacy-style LNB signal. Be warned though, the thing isn't pretty - it's not designed to sit under a telly in the living room - and it's also far more expensive. This is the Triax TMDS42C switch at around £90. What you will get though is four outputs: two for a legacy/gen-2 Freesat boxes and two for a gen-3 box.
Currently you have TV in other rooms of the house using the Sky Q mini boxes. As you know, this is a wireless solution for most people. There's no equivalent to this in the Freesat/Freeview recorder world. This means a return to cabling for either Freeview or Freesat.
Whilst running sat cable all over the house is an option it's generally not pretty, not that practical, and it's expensive relative to Freeview. It's not just the cabling, but if you want more than one recorder plus a couple of TVs just with Freesat reception then you're looking at an LNB with 8 outputs or going for a thing called a multiswitch. The signal and distribution gear will cost the equivalent of roughly a year's worth of Sky Q subscription. You'll then have the additional cost of any Freesat receivers/recorders on top. (Obviously this will be lower where some/all of your TVs are dual tuner models with Freesat built in.)
The least intrusive and potentially lowest cost solution for live TV is a return to Freeview. All flatscreen tellies have a minimum of a Freeview tuner built in. Newer sets have Freeview HD. It's there, so why not make use of it.
Unlike Freesat/satellite which is either difficult or expensive to distribute, Freeview is very simple. One cable can loop through a twin- or 3-channel recorder and then go on to the TV and feed all with signal. You can't do that with satellite signals. The aerial distribution gear is relatively cheap and requires very little technical expertise to do a DIY fit. A lot of houses already have aerial cabling installed; why not use it?
Even if you need to replace an old or broken aerial, the cost of that is typically less than £150 - and sometimes far less where the bracket and downlead are still in good order.
Humax is still the Freeview recorder of choice, but it's not the only game in town.
I like the Humax HDR1800 and HDR2000 Freeview recorders. They're out of production now, but can be picked up as used or refurbished for sensible money. Personally I would absolutely avoid the Humax FVP-4000T. The software/firmware was a disaster and it was never fully sorted. The FVP-5000t was its replacement. It's actually the same box but with better software. IMO it's still not 100% though.
There are digital TV recorders such as the Teknikal for £20 or less. These connect either via SCART or HDMI. They receive HD as well as SD, and they use the Freeview TV guide. Add some USB memory and you'll have a Freeview recorder for not much money.
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