I've found a good source of thin wire from SWG20  (0.9mm) to SWG34  (0.234mm) silver or gold finish, reels of 9M £1 (also reels of 22M) sold  for stringing beads in jewelry making.

https://www.therange.co.uk/hobbies-crafts/hobbies/jewellery-making-supplies/cords-and-wires/trimits-beading-wire#613451

a handy SWG conversion at
https://www.rapidtables.com/calc/wire/swg-to-mm.html

I had a look on an N gauge sellers site, handrail wire, 4x120mm pieces £2.20, if you work that out for the cost of 9M = £41.25 (9/.480 =18.75 x 2.20)

Hi Mike,

Useful for fencing wire, stays, washing lines, etc. Bends easily as well. Too soft for pick-ups.

P/B wire from Tichy Train Group down to swg 36 (0.08") is $2.50 for 10 x 8" lengths (2 meters). Cheaper at shows. Somebody is making a lot of money on this your side of the pond. Easy to solder. And comes straight.

Nigel