Happy Christmas to you too Catherine and everyone 🎄 Sorry to hear about the car but I'm glad to hear you're okay, a lot less replaceable than a car after all. Lovely to hear from you again.
Microbius, I agree the charity shops around King's Road are very disappointing, everyone on this board always goes on about them as if they're some sort of holy grail of charity shops but that wasn't my experience. Maybe if you live/work nearby and can frequent them often you have more luck? I thought Pimlico had the best charity shop offerings when I was last in London doing the charity shops, but I'm too much of a lazy fucker and just head straight to the consignment shops instead, Pandora's has my highest hit rate but there's a few others I like too.
I don't own any non cashmere knitwear from Margaret Howell but I have seen it, the itchiness will go, it's one of those quality in the long term things, if you make it softer you lose some of its strength, only certain types of wool are not itchy naturally.
In terms of sewing machines, definitely Bernina for a secondhand one, the mechanical models (electric but without a computer) from the late 80s/early 90s are the holy grails and as a stitching machine will outperform the new ones, the 930 or 1020 model being the most coveted ones. You can get one of the sister numbers for less (910, 931, 1030, etc) but they'll have less bells and whistles. It's mostly decorative stitching and you can do buttonholes, etc. Husqvarna and Pfaff also make good old machines but I don't know model numbers, just avoid any with a computer plate in because this is the thing that'll break down and be difficult to replace. Also, preferably buy from a dealer or at the very least one that has a record of being regularly serviced, if they've been sitting in a cupboard and fed the wrong oil it could be an expensive mistake. I don't have much advice on a new one, I have a cheap newer one (it's probably twenty years old by now but it was bought new as a present and only recently getting any frequent use) and it's fine for just straight things but it struggles through layers of thick fabric, but it hasn't hindered me much. Now I that I'm more serious about sewing I'm on the lookout for an old Bernina but finding one from the right year to have specific function with all the useful additional feet, accessories at the right price from a trusted seller is a bit of a waiting game. The new ones have all sorts of bells and whistles and make life easier in a way (self threading, fully automatic buttonholes, etc) but I find most of the fancier models are aimed at quilters, for clothes you really don't use much more than a straight stitch or the occasional zig zag, an old trundle Singer would still do the job.
Flo is more in the know with pattern companies than I am as I prefer to draft my own. For pyjamas for the whole family I wouldn't recommend self drafting that to someone new to it but I would encourage you to in the long term as most patterns will have the same fitting issues you have with regular clothes. If you're making trousers that are not ridiculously basic and need more length for example just adding a few inches doesn't always work, position of the knee, seat height, etc. would all ideally be adjusted to your measurements and when you start altering a pattern that much you may as well start from scratch with a self drafted basic block that you can use over and over again and a good patterning book. One thing I also dislike about some patterning companies is that they assume you'll have/use an overlocker for seam finishes and either offer shoddy alternatives like just a zig zag or none at all. The whole point of making things myself for me is that I can create things of higher quality than in a factory, make hand finishes that take forever. Home sewing is not something you can do on the cheap, it's really cost and time inefficient. I spend a lot of time on it and enjoy the process of it all but I don't want something that's quite rough looking on the inside as a result, I don't particularly like the look of overlocked seams either so don't want to own an extra machine either.
I have heard that the Eastwood pyjama trousers for men are very popular with spouses/partners of a lot of sewers (I'm sure there are some male sewers who like them for themselves too).
In terms of linen, you'll want to get some that have been softened, like a stonewash finish because otherwise it will itch like mad before you manage to soften it with wear and washing and beyond a cute family photo I doubt anyone will want to wear it again. Not too heavy a weight 120-175g ish. Nothing beats shopping in person, linen is very sustainable and you can get locally produced if you look for it. I swear by Libeco linen as that's somewhat local to me but I think in the UK you should look at the Northern Ireland producers. I'm trying to remember the name of one that works for a lot of big retail companies and they have a consumer site, McB something, someone on here will know who I mean.