I have it on reliable authority that the first Viking to be returned to service from Southern Sailplanes was billed to the taxpayer at a figure in excess of £100,000 New ASK21s are around €80,000 to buy. One really couldn't script it!
Given that the task is to fix (hopefully) upwards of fifty Vikings, how much of that quoted £100,000+ is for tooling and processes to do the overall task more efficiently than a one-off repair at 'One man and a dog in a shed' would be?
The RAF are also no doubt asking for the civilian repair organisation to operate to RAF procedures, which could well be long-winded and require people to be spending time on project plans, progress updates and all the other time consuming but non-productive activities which go into a typical MOD programme. If people have had to be brought in who are already familiar with those activities, they won't be free.