Not to even pretend I'm saying something you haven't known all your adult life: British resistance to the Eurozone has been well entrenched so long that it was the stuff of sympathetic jokes for 1970s sitcoms (Yes, Minister comes to mind). And I will honestly profess a long standing sympathy for it just by way of a confession.
Still, I'd like to suggest that Britain could not "save the Euro" even if she had adopted it at the beginning.
The problem is that while the Euro's value is representative of the strong economies that back it it has become with respect to the weaker economies terribly overvalued compared to where their own currency would likely be had they stayed with them. That is good news (actually: great news) for those with savings in those nations with issues; however, not having control over their own currency seems to have played a real part in their woes too.
Long ago a certain infamous banker opined that he didn't care who made the laws if he controlled the money.
Now, the Euro isn't some dark foreboding conspiracy but what was said does speak in part to how these problems have risen. The idea being that countries with spending problems will, if they are able, often try to use monetary policy to get themselves out of their woes in such a way that the proverbial can will at least be kicked down the road.
This is happening right now in the US with the Fed quietly qualitative easing (we're approaching QE3 now ... there should never be anything "QE" that isn't a ocean liner), easing huge quantities of money into circulation which has helped drive down the Dollar vs other currencies and I suppose the net result that they hope for is to monetize the debt without causing inflation (I don't know if you've heard this but it has been suggested that at this time the US might be in a deflationary phase were we not printing money faster than a Christmas elf makes toys).
So, in the same spirit that people are always preparing to fight the last war (the Trident you mentioned?), it seems reasonable that politicians are likely to be using too-old playbooks too. The idea is that their domestic policies could arguably be exactly the kind that they would have had if their own central bank still controlled their currency ... but they don't. So any ideas they may think work when a nations get into these messes just won't all because they may make the laws but they don't control the currency.
So where they might have attempted to monetize their debts in hopes that both they and their creditors won't loose everything ... they can't. Essentially the Euro has become their new gold standard and the only way they get this expensive money is to borrow it from those who have it.
On the surface that sure seems better than printing money certainly seems saner to me but it means, so to speak, that they've no passing game to complement running the ball.
As such, Britain would be just one more reason the Euro was strong but not a cause for why those whose domestic policies have now got them holding out their hands would be doing any better.
So I really wish you all the best and kinda hope you keep your own money. If the Euro can't be saved and it probably can't be if what I've said above is remotely accurate it may signal possibility for a brighter tomorrow just because your money may still be seen as sound by comparison.