I'd see this as a huge setback for the UK space industry and planetary exploration in general. Beagle 2 was a textbook case of how not to run a project, giving the impression of an attitude of "leave no corner un-cut". A few consequences of it somehow by a fluke managing to land and operate as planned could be:
1) We get more good science of Mars. The results of the effort to detect methane would be especially interesting.
2) Colin Pillinger gets a knighthood and a massive ego boost. He immediately pushes for a follow-on probe.
3) The lessons aren't learnt from Beagle-2. A mutated strain of Victory Disease takes hold, and there's a wider push for super-low-cost space missions on the Beagle model. Any projects that make it to launch do not roll the three sixes Beagle-2 somehow managed and fail. Because the totally inadequate monitoring telemetry of Beagle-2 is not seen as a problem and so is never corrected, we never find out exactly why these failed.
4) Before they fail, the success of the low cost Beagle-2 puts political pressure on NASA to reduce their own costs, especially the spiraling budget for the Mars Science Laboratory rover (a.k.a. Curiosity). This belated revival of the "Faster, Better, Cheaper" crowd, combined with Administrator Griffin's attitude of "we know what we're doing, no need for detailed analysis of other options" (see also Ares-I), leads to inadequate testing and MSL's failure. This in turn makes Congress unwilling to fund similar large, Flagship projects in the future (despite the fact it was pressure from their side that drove the MSL failure - see also Commercial Crew IOTL, where Congress justifies cutting budgets based on delays caused by them cutting budgets...).
5) Britain's standing in ESA is weakened, as they try to force more Beagle-style missions piggy-backed on ESA probes. ESA hated working with the Beagle team because of the lack of professionalism and the late changes it forced on Mars Express (after promising to stay within parameters). They will not be happy at having to repeat the experience.