Unofficial LEGO Sets/Parts Collectors Guide - From 1966-72 UK/Australia switched to using mostly the same spare parts pack as earlier, but switched from 2xx to 4xx pack numbers. These boxes finally were
PLEX Technical Parts Set, 328 Pieces Technic Parts Set, Technology Building Blocks Components, Compatible with Lego Replacement Parts : Amazon.co.uk: Toys & Games
LEGO Parts
Buy, Sell, Trade & Create with pre-loved Lego® bricks, sets and figures - bricktraders
LEGO DUPLO REPLACEMENT Parts / Pieces / * You Choose* - #1 £2.28 - PicClick UK
REPLACEMENT PARTS FOR Lego Krusty Krab 3825 ~ 2 Flags £6.06 - PicClick UK