Everyone should remember though where Whitworth is mentioned this is only the Spanner size - if you are replacing the fixings these threads are BSF (British Standard Fine) which is 1 size larger than Whit. i.e. 5/16BSF thread uses a 1/4W spanner size.
ENGINE
ROCKER COVER 5/8 AF
FAN BOLTS 7/16 AF
WATER PUMP NUTS ½ AF
THERMOSTAT HOUSING NUTS ½ AF
ROCKER PEDASTAL NUTS ½ AF
CYLINDER HEAD NUTS 9/16 AF
MANIFOLD TO HEAD NUTS ½ AF
SUMP PLUG ¾ AF
DISTRIBUTOR CLAMP BOLTS 7/16
OIL FILTER STUD NUTS 9/16AF
OIL FILTER PIPE ¾ AF
DYNAMO /FANBELT ADJUST TOP ½ AF
DITTO BOTTOM 9/16AF
STARTER MOTOR MOUNTS 9/16 AF
TIMING CHAIN COVER 716 AF AND ½ AF
SIDE COVER BOLTS ½ AF
SUMP BOLTS 7/16 AF
STARTER DOG ¾ WHIT LONG SOCKET
CLUTCH COVER BOLTS ½ AF
FLYWHEEL BOLTS 9/16 AF
ENGINE PLATE BOLTS ½ AF
ENGINE MOUNTING TO ENGINE BOLTS ½ AF
GEARBOX TO ENGINE BOLTS ½ AF
BIG ENDS 9/16 AF
MAIN BEARINGS 5/8 AF
CLUTCH
CLUTCH ADJUSTMENT ½ AF AND 5/8 AF
GEARBOX AND REAR AXLE
FILLER AND DRAIN PLUGS 3/8 WHITWORTH
GEARBOX COVER PLATE NO 3 PHILLIPS
UJ BOLTS AND NUTS ¼ WHITWORTH
DIFFERENTIAL TO BANJO CASING ½ AF
GEARBOX SIDE COVER NUTS 7/16 AF
EXTENSION BOLTS 7/16 AF
REMOTE CONTROL TO GEARBOX ½ AF
REMOTE HOUSING TO BOTTOM PLATE 7/16 AF
REVERSE PLUNGER PLUG 11/16 AF
GEARSTICK DAMPER PLUG 4/4 AF
BRAKES
HANDBRAKE ADJUSTMENT NUTS 5/16 WHITWORTH
MASTER CYLINDER FILLER 7/16 WHIT OR PLUG SPANNER
BLEED NIPPLES 7/16 AF FRONT 11 MM REAR ?
BRAKE PIPE UNION 3/16 WHIT
FLEXIBLE HOSE NUT 3/8 WHIT
BRAKE BACK PLATES ½ AF
REAR BANJO BOLTS 5/16 WHIT
CHASSIS
WHEEL NUTS 3/8 WHIT
RADIATOR BOLTS ¼ WHIT
HOSE CLIPS 9/32 AF
BUMPER NUTS 7/16 WHIT
FRONT HUB NUT 15/16 AF
STEERING ARM TO TRACK ROD END 3/8 WHIT
EYEBOLT PIVOT 9/16 AF
LOWER ARM BOLT 5/16 WHIT
FORK NUT 3/8 WHIT
TIE ROD TO FORK FORK NUT AND BOLT ¼ WHIT
TIE ROD TO CHASSIS 5/16 WHIT
LOWER TRUNNION NUTS 9/ 16 OR ½ AF
UPPER TRUNNION FULCRUM PIN NUTS 7/16 OR ¾ AF
WINDOW ASSEMBLY 3/16 WHIT
DOOR TO A POST ¼ WHIT 13 MM IS A TIGHT FIT
FRONT WINGS ¼ WHIT
HOCKEY STICK NUTS 3/16 WHIT OR 4 BA
STEERING WHEEL NUT ¾ WHIT
Those from Peetee, and from Harry Mango -
Hockey stick nuts are 2ba as are Top chrome, Bonnet Flash, Bull Badge & MM/S11 Boot Badge
kick plates should be 3/16W
A few more from memory :-
Eye Bolt 1/2W
Rear Hub Nut 1,1/8W (although 1,7.8 AF is a very good fit & works)
Diff Pinion Nut 1,1/8AF
Tappet adj nut 7/16AF
Front Panel lower 3/16W
Front Panel top 1/4W
Bonnet & Boot Hinges 3/16W
Bumper Blade to Valance 1/4W
From ChickenJohn:
a few more for you:-
rear wing bolts (saloon/convertible) 1/4 Whitworth
front seat mounting bolts 1/4 Whitworth
engine mountings to engine bay floor bolts 1/4 Whitworth