No!!!
71725 was at work in the stone crushing etc area.
There is a picture of it in my report:
http://www.internationalsteam.co.uk/...lers333.htm#89
I asked about this portable last year and none of the volunteers knew of an identity.
A second Marshall portable # 45028 was at work near 71725. The 4th Marshall portable (in the log yard) is also unidentified.
Of course, there are numerous unidentified such engines at the end of the Marshall list in the TER. Given their origin and condition, it is unlikely they will ever be identified.