I have several questions on the central locking issues, I also only have one key for my TD5 2001 which concerns me for obvious reasons.

I originally had the "American" locking thing where only the drivers door opened on the key remote at the 1st press, 2nd press and all doors opened remotely. after a few months it is now 1st & 2nd press and all but the drivers door unlocks which then has to be opened with the key.
I am assuming this is a common fault and it is something to do with the drivers door solenoid ?
The other confusing thing (amongst many ) is I took my precious 1 key to Timsons and they put it in their machine and told me there was no transponder so I had a standard key cut as a spare. I got home and unlocked the car with the remote and started it with the new key :bounce:
I then thought ****e I had the oem key in my other hand so went and put it in the house and came out and tried again , got dash lights and heaters but no start :wtf: I tried a few times then thought better stop now as if I knacker this I am going nowhere in the motor.
So in summary how do I fix the drivers door unlock and does the original key have a transponder or no ?
Currently I have an ebay special original type key with the blade cut but the remote fob bit is empty and a standard type key cut to fit door and ignition

for the driver's door you must replace the latch assy(it's not a solenoid, it has two motors within and the door switch), about the keys, there are two things which must be sync'd, the coded signal to the roof receiver to unlock/disalbe alarm and a transponder which must communicate with the passive remobilisation exciter coil which is around the ignition barrel, this one has effect only for starting as if the transponder-coil dont comunicate it' gets immobilised...what you can do is to get it plugged in a tester and disable the passive immobiliser or you can try to unplug the coil and see if it starts this way(it might but not 100% sure)...i can't answer you if your key has or not a transponder, if it's OE it must have it but you must sync it with BCU

Thanks for this , it does seem a particularly complicated system for a 2001 vehicle, as I said locksmith said no transponder / chip in my key so do not under stand how the cars systems are interacting with the key. It either has a chip which is coded to the ignition or not, locksmith says not ?

what's certain is that this issue is not to be discusssed with a locksmith... and to give you a better answer i should see that key myself... which is a bit difficult at this moment

That's true