If you have any more suggestions re the snps I have, I'd be grateful
Actually it's the rs numbers that really define the SNP and make it easy to search for. The letter designation is an older form of description which does tell us something about the actual change in the variant but makes it difficult to find if you know nothing else about it.
Some of the letter descriptions have become familiar because of their popularisation by Yasko and they get discussed over and over again on the internet (often incorrectly), so I can identify some of your SNPs. However I would need to know the rs number to comment on many of them.
Here is a recent thread which canvassed various resources which can be helpful in understanding SNPs.
What I can say about the ones you list is as follows
The AGT variant is not very significant clinically, is associated with higher plasma angiotensin and higher bp, GG variant responds well to atenolol (I have that SNP but my notes are not very comprehensive and date from a time before I realised that most of the early association studies mean nothing - too small and inadequate statistics).
BHMT 08 little to no effect, CBS no effect.
PEMT rs7946 is a loss of function variant associated with non-alcoholic fatty liver disease. It definitely slows the formation of phosphatidyl choline though I haven't recorded by how much. OMIM would probably tell you. With +/+ you should definitely be ensuring there is plenty of choline in your diet and probably supplementing also - choline and/or PC.
Here, here, here, here and here are threads discussing some of the SNPs.
+/+ for the loss of function FUT2 variants definitely has an effect so you should check these out. They seem to have an adverse effect on gut microbiota as well as affecting B12.
I don't know the actual rs numbers but it could be that your combination of several +/+ for MTR and MTRR, possibly with FUT2 thrown in, is seriously impacting B12 metabolism and making a significant contribution to your pernicious anaemia.
I don't know about the TCN SNP but it is a cobalamin transporter so worth checking up also.
The best way around this may well be just what you are doing - topical B12 (both forms) - plus of course all the other things that support this and related pathways.