I may be wrong but I believe that dealing with non mil SAR out to 30 West belongs to the Dept for Transport. Therefore, it is their problem if they do not have the necessary resources and nothing to do with MOD.
Oh, and one for Leon. Nimrod topcover for SAR trails was all about time. Had you banged out of your F3 on the way from ASI to MPA, which incidentally is nowhere near any shipping lanes, an MR2 would have followed you down, marked your on-top very quickly and dropped ASRA kit to give you a much better chance of survival for the number of days spent bobbing around the Southern Ocean (protection,location,water, edible candles, lots of PLB capability, fishing kit etc.) Using gas from the tanker and the fantastic Searchwater radar, it would then have searched for the nearest vessel to come and pick you up. All this probably happening before news of your ejection had been reacted to by the responsible SAR RCC. You may remember the F3 that had a Mayday, 1000nm north of ASI in 1997. Just made it back to ASI as the gearbox melted en-route!