Owing to the amount of time the rectification work took alongside how short the amount of time was left on the engine's boiler ticket, it was decided to abandon the mainline certification until after the engine's next overhaul was completed. An announcement from Didcot later on regarding the ceasing of mainline operations owing to costs and wishing to get more use of their engines, 6023 would now not be undergoing certification to run on the mainline. The only mainline journey it undertook, was to be hauled in light steam by 70013 "Oliver Cromwell" to a display at Old Oak Common TMD via London Paddington in August 2017. With mainline equipment no longer needed the engine was re-fitted with its original cab and later on its original height safety valve cover and chimney which also included re-fitting its original blastpipe. It made its final journey at Didcot before its boiler certificate expired on 13 September 2020.