Harry's right that this is not conclusive proof that the MAF is actually to blame. You could always test the output, by getting hold of an ODB2 reader such as this one, £7.98 on eBay -
http://www.ebay.co.uk/itm/New-ELM327...item3cc0168b68 - and using it with Torque Pro on an Android smartphone. The figures it should be producing are given in this thread:
http://www.the75andztclub.co.uk/foru...d.php?t=195871.
In your position, though, I'd be inclined to just buy the MAF sensor for £75 and if it doesn't solve your problem, sell it on here to someone, I'm sure someone would snap it up for a few quid under the going rate.