Seeing as I'm a Brit I thought I better give my input on this one!
If you want a REALLY authentic Best recipe, I would suggest this one, supplied by the brewery themselves for the book, 'Brewing Beers like those you buy' by Dave Line which is considered the homebrew bible here in the uk!
I chose this one because it's my favourite Best Bitter, and because it's usually made only with hops and barley grown within my county (Sussex).
The beer is 'Sussex Best' and it's brewed by Harvey & Sons brewery who are based a few villages along from me in the town of Lewes.
'Harvey's Sussex Best Bitter' Original recipe from Harvey's of Lewes
6lb Crushed Maris Otter Pale Malt Barley (or other pale malt barley)
8oz Flaked Maize
8oz Light Brown Sugar
2oz Goldings Hops
1oz Northern Brewers hops (quite bizarrely, these are grown in sussex as well!)
1tsp Irish Moss
2oz Light British Ale Yeast
Bring water to 60*C and add crushed malt and flakes
Raise to 66*C & mash for 1.5 hours
Sparge grains
Disolve sugar in a little hot water
Boil wort and add hops & sugar and boil for 1.5 hours.
Pitch irish moss as per instructions
Ferment 4-5 days until SG reaches 1010 and rack to secondary.
Disolve gelatin finings into hot water and add to secondary whilst racking - Do not boil the gelatine for gods sake!
Leave for 7 days
Rack beer off sediment into keg or bottles and carbonate (use dissolved brown sugar for bottle carbonation)
Leave in keg or bottles for 7 days to condition before sampling.
I'll leave you with a pic of a pint of Harvey's Sussex Best I took in my local last summer!

- oneleg