All,
Very sorry for not coming back to any of you on this. I expected to get email notification when someone replies to my post and I did not so I thought no one had responded.
@Herbie - Thank you for people updated
And thank you all for your suggestions.
Current state of affairs is as follows:
The car was towed to a mechanic who replaced a spark plug and cleaned the fuel injectors to clear the deposits within them (soaked and backfed them in his words). The car ran fine for maybe 50-100 miles and then started to misfire again. We have decided to replace all the fuel injectors. I have bought used fuel injectors from an eBay seller in Lithuania (will take a few weeks to arrive, if anyone knows a quicker way please shout) because new ones cost a fortune. Once the new injectors are in we should be ok.
Thank you again.