The Perrier drawings aren't perfect, and I think the Spink drawings were are attempt to correct them with some success.
I believe the Hewson's are producing new detailied drawings from works drawings, however their website hasn't been updated since 2014 and no shows very little, instead directing you to download the latest catalogue, which is also 2014.
The tender in any case is a standard BR item, of which I think Dave (VulcanBomber) is building about 20..... The Les Warnett drawings for it (as used for his 9F) are I'm told pretty good.
Got: 3½" Lilla, 5" Lion, 2½" Annie Body.
Building : 5" Edward Thomas/Peter Sam, 7¼" Jubilee1897
In planning : 4" Burrell Road loco, 5" Standard 4 tank
Would like to build : 5" Duchess, NGG16 Garrett
Jubilee building photo gallery - photobucket please follow me if you have a photobucket account
The Warnett Drawings aren't to bad for the tender, if your looking from the outside in. The drag boxes are entirely different to the full size but the lower stretchers are good copies along with the upper ones.
In the end, the Warnett Drawings were used with the perrier Britannia's.
I do have brake blocks spare to the Warnett Drawings if you want some?