I've been through this on my non pd leon and still slowly working on it. My wife's Audi A2 has mayo on the dip but not the filler so hoping it is a low use issue rather than head gasket. I have just bought a basic combustion tester kit for £23 off ebay, I think it could be a good purchase for now and the future, think it will form part of my inspection routine when I buy a car!
A mobile mechanic quoted £600 to change the gasket but then found the cams were well rounded so the cost went to over £1000. Not worth it for the value of the car so have chosen to do it myself.
I found an engineering firm that supplied a remanufactured head - cleaned, skimmed, valves reseated etc for £120 delivered. I have checked the head for true and it is.
There is a seller on ebay who does full head gasket kits (not cam cover though) for £43 del. EuroCParts seem to be the cheapest for head bolts at just under £17. Add on Oils and filter and I hope to get away with a total under £300... Just need to work out
how to do it, not too many youtube videos on it
Think I'm getting there though.
As a thought you may also want to check when the timing belt and waterpump were last done, now would be a great time to replace.
I like the last 2 suggestions by Pimped up vario, I have vag-com so need to see
how to run the injection test.
Also, just a thought for you I have the 130 cordoba as well but wrote it off when the bonnet let loose on the motorway, all is good apart from the bonnet, windscreen and roof. I have it on ebay for spares or repair and many people state it is easier to slot a new engine in than replace the head.