A couple of years ago I thought the same I couldn’t find a 28 frame in the UK so I got one from Japan with nova sorted, that’s when the misery started, couldn’t find a decent rear end with linkage so back to Japan £500 later and then the 17 rear wheel I found one black se wheel perfect condition with rear brake assy another £500
Then the cheapest part the loom and pgm 4 that is when I bailed out and fitted HRC loom with pgm 111, that was 2 years ago and bits have marched on in value since then,
The problem is 10 years ago the Japanese just wanted to sell but now they want them back and who breaks a 28 up when altogether they command a kings Ransome
Good luck anyway
jonmac