My dad and I went though his Lego from when he was a kid and we managed to build his weetabix castle, he used to collect vouchers from the cereal boxes. It
Castle before Castle | Brickset: LEGO set guide and database
LEGO Weetabix promotions | Brickset: LEGO set guide and database
LEGO WEETABIX CASTLE FROM 1970 - The 1st Castle but Is It Rare??? - YouTube
00-7 Weetabix Promotional LEGO Village | Brickipedia | Fandom