I am aware of this as well as where he drew his influence from don't worry. The picture I posted as simply the first one that i saw and posted as I was going out the door for vacation.I think what glove was referring too is the fact Tolkien drew a lot of his inspirations for Rohan from the Anglo Saxons and some Northern Structures (Namely Hrothgar's Hall from Beowulf). In this respect it wouldn't relate at all to a Norman style castle, more related to Anglo Burgs, which were generally semi-fortified fortresses with basically an entire city within them.
Tolkien even put 'Burg' within the name. Also it fits much more with the vague description given of Edoras as having an earthen/stone dike-wall with a spiked fence upon it, I'd most likely assume Aldburg would have the same.