Midas Cars Forum - www.midascarsforum.com

being cynical as I am checking your engine doesn't make them any money, unlike checking your tax disc so they would typically not be anywhere near as helpful.

Is there any limitations on how long you've had the engine? The contents of my rainy day shed have been there nearly 10 years since I moved up from the smoke I'd struggle to find reciepts for a quarter of that stuff.

For a while, I was a member of the "Institute of Automotive Engineering Assessors" (an overly grandiose name for what they were), and made several inspections for engine changes etc. In some cases, letters from "a garage" would not be accepted, at this point I came in. In other cases, letters from a garage would be accepted. I could not work out why the difference.
Your local automotive assessor/consultant would help. There are still many private ones around: I think J. Lloyd in Liverpool is still operating, but their nos. are diminishing. Your local recognised insurance repairer would definately know your nearest assessor (their seen as a pain in the arse!)
For my experience, with Adrian Flux, premiums for a Midas with any engine from 1275 up to 2 litre were all the same. (and no, I didn't stick a 2 litre lump in my Midas; I just asked the question "how much and how far!!!")

we recently went th rough this with Ruby - when we bought her from Russell she had a standard 1275cc engine as the bored out engine shown on the V5, Russell had swapped sometime before- I wrote to DVLA when forwarding V5 change of owner details pointing out cc was wrong - got a reply saying needed to show with evidence engine change and having explained to them Ruby is a kit car with DIY en gine swap they accepted a letter from Russell with letter from supplier of the 1275 engine (not a garage) as sufficient evidence and correct details are now shown on the new V5

The Mk 1 I have just bought came with a 1275 engine in bits with an engine number that was different to the one on the old V5. When I sent back the new keeper's section, I filled in the new engine number.

I got the V5 back today (new engine number on it) with no questions asked. It seems if you want your car to have another engine number, sell it to someone else!