Heljan 00 Gauge Class 07 29121 V1 Peakstone Yellow.  Bought new by me, very little use, being sold as concentrating on BR Blue - sale is a wrench as it is very nicely detailed and runs very well (see video) with all lighting working as described in the Heljan paperwork, i.e. the red and white lights show on the same end in direction of travel, before anyone asks.