Back taxes on cars

Help needed

I about to move to Greece and have been offered a used car which has been off the road for around 12 months.  The car is fine as a cheap run-around and is in good condition. It's ideal for my purposes. 

However, I have been told by some people that I need to pay back taxes from the time the last road tax expired, before I can put the car back on the road, and "there could be other charges".

Can anyone confirm the need to pay these taxes and give me some indication of the 'other charges'  that may be involved.

The car in question is only worth around €2000, but if the back taxes etc start to build up, I may be better off just getting something else which already has a valid road tax.

Any ideas or advice ?

Thanks in advance.