Regarding improving visibility of the numbers - I've tried pencil graphite, permanent marker, oil and then heating with a paint stripper, etc etc. However the photogrph you can see is the best result I've got and this was with a photoshop type filter. When I took my photographs (with my I-phone) and illuminated by an LED torch, the numbers did not show up at all (to the naked eye) whatever I did. I decided to look at each of my I-phone photos on a large screen - and surprisingly I could read them. The one I attached has a pale blue filter which enhances the digits just about enough to be legible. I am going to supply this photo to the IVA tester. I would imagine they are not expecting to be able to identify each engine by it's individual numbers - if there is an accompanying V5 document. However since I dont have one I think my evidence will need to be a bit more substantive. To get this photo I had to drain down my radiator , disconnect the hoses and air filter and MAF and sundry knock sensors and other electrics.

I'm hoping I wont have to do this on Test day!

Thanks for all the suggestions - and Chris you read the number correctly . (I was initially confused by the continental "1's" mistaking them for 4's - and the "R" from the initial AR is rather stylised ) The only other thing I need to try and get is an image of my block casting date - which I know is October 2002 - and am looking at getting hold of an endoscope . I'm thinking I can photograph the on-screen image.

Does anyone happen to have an endoscope they could rent out ?