What I am wandering is - is this BCD worth the effort? Is is a good BCD? or should I just bite the bullet and by a new one (Perhaps a Scubapro one) which is brand new and can be done locally?
The fact that you are asking this question is that your gut is already telling you something.
Unless you are emotionally attached to this BCD because it equates to whatever was the British/Scotish version of the Chevy Impala that you got laid in for the very first time, you should follow the instincts that led you to ask the above question in the first place.
The reality is you were donated this BCD, so the emotional attachment eluded to above, does not exist....hence, the answer to your question.
I am not opposed to using older gear...hardware (metal, such as regulator 1st stages) fares better with age and use if taken care of than softer gear made from fabric and plastic.
Or you can conduct a £200+ experiment...and if/when you make it back, you can tell us all about it.
-Z