I'm sure I read somewhere that Britain went halfway around the world - a couple of hundred miles away from a another nation and won.
If you would have wanted the dictatorship to win then fine - it's a free country.
As for Iran, you are right, Britain could not go to Iran and win conventionally. As Vietnam or lebanon showed even if you are better regiment to regiment other factors mean you fail.
But then you are presuming Britain would have to go to Iran. Could Iran come to the UK and win - erm no.
True...
There are enough Islamist in Iran, they dont need Londonista ones...