I did an extensive search for a fitting guide for this locomotive, and didn't find one anywhere so here is my guide:   The loco in question is R2225 Princess Arthur of Connaught in LMS maroon. The loco is loco drive, but not DCC ready. Mine was bought new, but has sat unused for several years. This is how I did the installation, usual caveats apply that you need to wire it properly to avoid damage to the loco or decoder.   I had an 8 pin Hornby decoder with a damaged pin, so