I had a logged time of 3.30 for this, coming (I believe) from a European 45 label. However I've amended this to 3.27 after more investigation.Version of Chi Mai on Private Stock records from 1978 is now available digitally running 3 29 which is the same as it's 1978 7" single whereas the BBC version runs a couple of seconds shorter so I think 3 29 is the proper single edit for the track.
There's a UK BBC 1981 45 on YouTube plays 3.27, which exactly matches the BBC TV Themes CD I referenced earlier.
10 seconds from the start of the final note (3.17) and the audible end of the fade out.