Pointy SV rear cyclinder missfire - help?

Hi everyone...
As you can see from my join date, I've been lurking on this site for a long time, but not really got round to posting yet! Needless to say, the site has been invaluable to me, and after taking nearly 4 years from passing my test to buying my first bike (there were a number of circumstances which prevented it, but that's a whole other story) my first bike was always going to be an SV.
So, I bought the bike at the beginning of April and use it to commute every day. I live in London and despise anything public transport related, so in the 4 months of ownership I've clocked up nearly 3,000 miles and have loved every second.
However, on my way home last week, I stopped at M&S to get my dinner, and when I returned to the bike and tried to start it, it wouldn't fire up - it was turning over fine, just wasn't igniting. I tried again, and just after firing up there was a 'pop', a grumple, and then it cut out... leaving behind a slight smell of petrol. As I was only 1 km from home, I wheeled it back in my leathers and did a lot of sweating.
When I got home, I managed to start the bike but it was running so rough, with a definite miss-fire. I left the bike and waited for it to cool down before starting it again and holding my hands on both the front cylinder and rear cylinder exhaust outlets to see which one wasn't getting hot - the rear one stayed completely cold whilst the front cylinder heated up quickly as it should. Conclusion: rear cylinder isn't firing.
Called RAC to see if they could fix it, and they came over and said that it needs a garage to repair it.
Me being me, I always want to at least try and fix a problem before getting someone else to... out of principle. So, being new to motorbikes, I was wondering if anyone could advise on the things to check. I have bought a 2nd hand coil pack/lead and a new spark plug from eBay (total £21) and waiting for these to arrive, but is there anything else I should be checking whilst I'm switching these over - as in could it be something different other than these two?
Thanks for any help which anyone can give me... being new to bikes it's all unfamiliar territory compared to car engines!
Thanks again,
Bash.