Permanent Under Secretary Walker is perhaps the most blatant example, in a long line of blatant examples, of the pompous, ineffectual civil servant called in by the government to put a situation to right, but just ends up getting in the way of those who are actually solving the problem in the first place. Masters, Brownrose, Chinn, and now Walker, and each with diminishing returns. Sometimes, subtlety has been an elusive beast in Doctor Who.
I'm going to stand shoulder to shoulder with Doctor Who composer and Radiophonic Workshop archivist Mark Ayres and be two of the very few defenders, and fans, of Malcolm Clarke's score for The Sea Devils. Comments about Clarke's score have been universally negative, but I have always been won over by its quirkiness. The strangeness of the soundtrack, with its blurps and bubbles, meshes perfectly with the aquatic theme of the story, and I personally enjoy Clarke's theme for The Master more than Dudley Simpson's. Also, to have a story that is so close to a normal Doctor/UNIT story, but missing one vital half of that equation, and have a soundtrack similar to other stories of the era would seem out of place.
Having watched The Sea Devils a few times over the years, I can't imagine any other score being used for it, and I can't imagine any other score that would have made the story better.