On the simple recording solutions front, I have been using a Zoom H6 and I think it does a descent job. When I want to go out to the porch or any other location away from my mix board, I grab the zoom H6, feed it guitar and vocal (and sometimes a mic on the cajon) and hit record. It is like having a little mix board, and the other zoom models of this type are similar. With the H6, I have the two provided mic channels, and then 4 more channels to plug in other sources (be it 1/4" or XLR). Each channel has a lot of parameters you can set, like phantom power or no, limiter, compressor, level, etc. You can also get an adapter that replaces the two built in mics with two more channels for other inputs. With that attachment, you can now connect up to 6 instruments/microphones. The record format can be anywhere from mp3 48Mbps up to wav file of 96khz 24bit. I think you can also record as a single stereo out or each channel independent. I have never even looked at putting out stereo signal, but you do have that by default as well with the headphone output. Anyway, great little unit IMO for about $350 (not sure what UK pricing would be). The adapter to get the extra two channels is about $90. Compact, easy to set up once you are used to where functions are, high quality record formats. I like it a lot!!! It's like a 6 channel mixboard that is about the size of a man's hand, and only about as thick as two hands pressed together. Records onto SD cards (have to be capable of a certain speed dependent to some extent on how many channels you are recording, each extra channel to record requires the card to be x amount faster to handle it) and/or you can use it as a audio interface with most DAW software. 4AA batteries that last me about 5-6 hours or record time (I use rechargeables). You can also have it run from a usb port power, but I don't use it that way much! Let me know if you want any more details or samples!
Your project is the bomb! Allowing us to live vicariously through your journey!! It's like watching a PS get built!!! Thanks for sharing ;~))