Magnet still do some, but it is on their trade site, AFAIK they only sell kitchens to the public. A carpenter, joiner or builder is likely to have an account.
Can you see this page?
much the same is true of Howdens
Premdor is a big maker and supplier, their products are sold in DIY sheds and Wickes, sometimes own-branded.
If it was me, I would either source a door myself (and preferably a frame) from a local supplier, and engage a carpenter to fit it; or find a well-recommended carpenter or joiner to supply and fit. They will know all the local sources.
In my district is a college that trains joiners, so we have more than enough of them for the work available. A competent joiner can make a door to your requirements, possibly better than you can buy readimade, and to match the style in your home.
Glazing a door is pretty easy, they usually come with pre-cut internal beading, and you use glazing tape, which is very strong and secure, in the rebate. A person who fits doors will be able to do it. They can also trim a frame or door to fit, make new beading if required, and fit your chosen locks and other door furniture. Door fitting is not a DIY or handyman job.
Pre-glazed doors are popular with housebuilders throwing up a thousand dwellings in the shortest possible time, but it will add to cost if you go to a boutique door company.
You can order glass to your whim. I now prefer laminated glass in external doors as it is very secure.
Not everybody hangs doors on stainless lift-off hinges, but I think they are best.