Which cartridge in a Nottingham Analogue?

FWIW, with a tonearm effective mass of 11.25 gms, which is "medium", you have a wide variety of choices. According to theory, a typical high compliance/low output MC cartridge will work fine in that tonearm but probably not super optimally, which, as you say, you don't care about. The good thing about having a tonearm with a lower effective mass than optimum is that you can quite easily increase effective mass by adding a mass to the headshell. We all "just want to listen" to our favorite music.

Audio-Technica AT-33PTG/II 0.3mV MC Cartridge

I think the Ortofon Black would be superlative...that's what I would do.

In the least you could do what I did and use a medium to high output MC cart. I have a Dynevector 20XH and use a MM phono pre amp. I am sure you get the idea. I think the sound is quite good but the real feinschmeckers will say it doesn't do MC the way the other good MC cartridge do. Ignore these naysayers and consider using one. What is choice of Phono stage, obviously make sure the phono stage has the option for MM which what I put my MC cart through. I use a Graham Gram amp 2 SE which is MM only, if want the option of true low output MC you'll need to pick another phono stage.

The late Tom Fletcher, designer of the Nottingham turntables and tonearms, was not a fan of MC cartridges and designed his tonearms to use MM carts. Based on weight, these arms generally work best with cartridges on the higher side of the compliance slope - I recommend a cartridge with a compliance value of 14 or higher.

Having said that, I have successfully used many MC cartridges with my Nottingham arms over the years. Being unipivot arms, tracking is always an issue. I have had very good luck with the Ortofon MCs and the Grado Statement and Reference MI cartridges. Based on experience I suggest that you stay away from low compliance cartridges like the Denon DL-103 series, among others.