I recently won a 25 kg of Durst Pale Ale Malt. Looking at the web, there is really no information on it. Can I assume that it would be interchangeable with a Belgian or English pale malt?
Sounds like it to me:
“Standard 2 row base malt for ales and English style beers.”
An English pale ale malt, yes. 3-3.5 SRM vs. 1.5-2 SRM for most “pale” malts. There isn’t really an equivalent from any Belgian maltster AFAIK.
I used to use it because the price was right and we had a good supply. The supply is not there now.
It is a decent malt, more flavor than NA 2-row Pale Ale Malt, but not as much flavor as a MO or GP Pale Ale malt.
Having used it before as well, I got similar #'s to Pauls. 
Same here.
I tend to substitute base malts pretty freely in my main favorite recipes, based on what’s available and what is decently priced at the time.
I’ve wound up using Durst quite a bit and can definitely say that it is good stuff and in my brews I find that it compares very favorably to the Brit malts that I still prefer. Inasmuch as I like consistency and repeatability in my 6 or 7 standard beers, usually after one batch with any substitute base malt, I can generally tweak my standard formulas if need be and match previous results from other products with no problem.
Bottom line is that the Durst will make very good beer.