Neopan 1600 and T-Max Dev - Grain and agitation

Ran a roll of Neopan 1600 through my Pentax MX, and developed with my standard T-Max Dev, 1+4 dilution. I usually use T-Max Developer because it often provides very fine grained results, but is this what you'd expect (considering the ingredients)?

(I appreciate that scanning exacerbates grain): http://i126.photobucket.com/albums/p117/chongy5/Roll59-Frame000.jpg

Additionally, can I confirm that these marks from the sprockets are from over vigorous agitation? I usually do 4-5 inversions every 30 seconds which works fine for the film that I normally develop (usually Kodak T-Max) but evidently it is too much/too vigorous for Neopan 1600: http://i126.photobucket.com/albums/p117/chongy5/Roll59-Frame013.jpg

If so, is it a case of less frequent inversions/agitations, or just doing them more gently? I appreciate it is a topic that has been discussed at some length so please bear with me - I have looked at threads where it has been previously discussed, but it is nice to have an answer given which takes into consideration my sample image

Thanks in advance for helping with the ever continuing learning.

The picture looks underexposed. My experience with shooting a lot of this film is the speed is not 1600, its 640, and pushing to 1600 gives WAY too much contrast and grain. At 640, developed for normal contrast, it looks gorgeous. It is not a fine grained film, but it looks sharp compared to films like Tmax 3200. Still, for ISO 1600, I think Tmax 3200 or Delta 3200 are overall better films cause they're less contrasty at those speeds.

How old was the film?

The meter is centre weighted so it may have been thrown by the lights. However, other pictures from the roll also exhibited similar grain and they were probably metered more accurately.

Newt_on_Swings, it was fresh and in date when shot and developed (and actually, still is - July 2012). I am in the UK and was lucky enough to buy the last of the Fuji remaining stock of Neopan 1600.

Hmm, we're your negs really thin? I find that the sprocket hole banding sometimes happens when I underexpose and shows up easily on the thin negs that don't have much density. The grain sometimes can get nasty as well when your scanner tries to compensate for a thin neg, or with the opposite, heavy fogging. Which was the case for a batch of p3200 I have, because of the age.