It seems I can do this without spending another dime. Good news! I will get busy and try that.
Meanwhile, I can get a little picky. For example, haven't I read somewhere that sound cards aren't usually good enough to make quality recordings. I can't possibly afford to spend $15k on a laser turntable and whatever else might be needed to go with it, but maybe I should consider a better ADC??
You have received quite a bit of good advice. There are a number of ways of doing this.
I would note that you have very nice equipment. For a start you have Quad ESL 63s, which puts you right away in the top 0.1% of systems on this forum. In addition you have those nice little classic L3/5 Spendor monitors. Spendor are another speaker manufacturer right at the head of the pack.
You are right to consider your Rega the better turntable. B & O are largely fancy interior design but not much beyond that.
I agree with Sterling that an internal sound card is not the best way to go. You should get that function out of the computer if possible.
I'm not sure why you want that Naim unit. All that can probably be done better with a good computer and external drives for storage. A computer can easily be put on a home network and stream where you want.
Now recording software is all different. I like flexibility.
So I do like to be able to mix with the ADC/DAC. If you want a voice over it is right there. I also like to be able to properly set the gain structure from analog to record and back. This is key to really good quality. This is essential for you, as your system will uncover blemishes most will not. I do like extensive monitoring and especially bit monitoring to make sure I'm not running out of bits. In addition I like to be able to set dynamic range, especially peaks to international AE/EBU specs.
Now I think it is handy to be able to quickly build a cue file. So this means you can set tracks with and without pauses, and set the pause you want. For this you need to work in WAV. Once you have set the tracks and got everything arranged the way you want then you can just drag the tracks into the cue file and save it. To then play that item all you have to do is open the cue file and the wav. will be found. You can then play any tracks in any order you want. Since you interest I suspect is classical, you can easily play just the work you want from an archived recording.
If the recordings are 16/44.1 then you can burn a CD straight from the cue file.
Spending some time researching which software is right for you is very important.
The other thing is, I don't actually archive many LPs. but I do record off the NET and have a lot of live concerts archived. You can make hot links to your favorite sources, like the BBC and MPR streams.
The possibilities are almost endless. A good and well set up computer system is part of the basics of any state of the art audio system now, in my view. It will do all you want and more and avoid add on units and units like that NAIM. I have two computers in my system, one for audio only and the other for AV.