My UK readers may or may not be aware of the bipolar relationship most Americans have with their homeland. For some, anything British is a priori good and, more than that, possessing an excellence so in advance of anything possible on this side of the Atlantic that they've managed to convince themselves that The Benny Hill Show must have hidden depths. For others, anything British is a priori bad and, more than that, exhibiting a pretentiousness of such a powerful sort that it's bamboozled a large number of young men into believing The Meaning of Life is actually funny.
In my experience, talking about any of the AD&D modules produced by TSR UK in the 1980s always runs afoul of these two contradictory points of view, with some people enamored of them simply because they're British-made and others disliking them for precisely the same reason. For myself, I found these modules to be, as one might reasonably expect, a mixed bag, with module U1, The Sinister Secret of Saltmarsh being one of the best low-level modules ever written for Dungeons & Dragons. I can't say for certain that there's anything "distinctively British" about it other than its spellings and vocabulary, but I don't think that matters much: its excellence transcends its origins.
What really stands out about U1 are two things. First, it takes the standard low-level D&D tropes -- an isolated town beset by problems appropriate for 1st-level characters to deal with -- and gives them a new spin. The town of Saltmarsh itself is given glorious life through its many NPCs, including criminals in league with smugglers who are using a nearby abandoned reputedly haunted mansion as their base of operations. What's terrific is that the mansion is not in fact haunted at all but is only made to appear so through the use of illusion magic and other trickery. The vast majority of the enemies the PCs face initially are in fact human, which puts the module very much in line with the traditions of pulp fantasy.
The second stand-out element of the module is the very matter-of-fact way it portrays a fantasy world. That is, U1 simply takes it as given that that the D&D rules describe the nature of the world and then goes about logically drawing out the consequences of such a description. The result is neither a low-magic world nor a world where magic becomes ersatz technology but rather one where magic is uncommon but potent and often used in clever ways. Likewise, humanoid races, like lizard men, are portrayed as being both intelligent and intelligible without falling into the trap of making them either cardboard cut-out mooks or misunderstood creatures hard done by human villainy.
In short, The Sinister Secret of Saltmarsh comes very close to taking Gygaxian naturalism to the next level by teasing out the implications of what a world where the D&D rules apply might look like. Combined with the low-key nature of the module's central mystery -- criminals using a local legend as a cover for their activities -- I find it hard not to gush a bit about this module myself. But I do so because it's a superb example of adventure design and not out of Anglophilia. Really.