Hmm...interesting, had another read through of the pre-amble and it looks like they're planning on treating these like plug and play solutions to a fair few war-like tasks.
I'm not convinced you can get that result out of a hull that cheap - and the speed thing would be a bind. I dunno, I suppose ASW has moved on a bit and it's more about the platforms you can launch than the hull. I shall peruse further..
How important is speed in the ASW environment, once the principle means of attack moved from ship mounted weapons (Limbo etc.) to their helicopter(s)? There is an irony that almost as soon as the RN abandoned the Type 41/61 platform, for really a retrograde step to the steam turbine powered Type 12/Leander, to get an extra 3 knots, speed became irrelevant with the arrival of MATCH/Wasp.
The real issue is trade protection vs. fleet escort. the need for speed is to keep up with carriers/naval partners etc. I actually think 18 knots for the savings involve is on the slow side and would prefer 24 knots as it would help with fleet work. But the thrust of what this paper says, is what a number of people have been saying on here for some time, numbers do count. Some of the other areas mentioned are actually not radical at all, it's fairly proven; StanFlex in particular, and certainly the way Phalanx is increasingly being deployed, even modern VLS systems.
It does say, it's not about a hi/lo mix, but I think this would also be a benefit, in the partol space. The current ideas around the Type 26, do not look much of an improvement over the Type 23. I would rather see less hulls but a far more capable ships c8,000-10,000, as flagships for small squadrons (say on 1-2 or 3 ratio), capable of operating sizable USVs.
A lot will depend on where the unmanned revolution goes, and the RN should be one of the leaders in this area; it has the potential to be a massive force multiplier, whilst reducing costs. For a helicopter based solution maybe something nearer MATCH/DASH, 2,000kg max take off weight, payloads like: 1-2 torpedoes, LMMs, sonarbuoys, or surveillance. For surface based craft, maybe something based around say Stiletto M80, this is currently configure to more special force, but for ASWit could do very long patrols often just drifting, to be liberated form having to provide facilities for crew and the increased payload for both sensors and weaponry (maybe spearfish torpedoes) over helicopters.