Motor Rail 21520 Re-Re-Power

Motor Rail 21520 has had what can only be described as a varied career, working both in Essex brickworks and Scottish Peat. It arrived at Apedale as little more than a shell, and was then painstaking restored, including an epic welding operation to build up the hollow wear on the wheels. It arrived without an engine, having had the previous Deutz unit removed; an Alstom air-cooled unit was used in its place, which fitted, albeit with negligible clearances. The loco first ran with this unit in 2019. Although it was powerful and easy to drive, the engine proved to be rather difficult to start. More seriously, the clutch began to make ominous noises, and this occasioned the loco being stopped for investigation.
One of the objectives of the original restoration was ease of maintenance, and this has proven beneficial in the speed with which cab, bodywork and the engine have been able to be removed. A second Alstom engine has been sourced and fitted, and the clutch problem has been located – a loose adaptor plate – and fixed. Since build the loco has now had at least six engines, of four distinct types – two different types of Dorman, Deutz and Alstom. Is this a record for a narrow gauge loco?