Many thanks one and all for your valued responses to my original question, they were all welcomed and given careful consideration. As suggested I eventually plumped for a full set of factory tinted privacy windows which have worked out very satisfactorily for me. Having started out thinking I'd make do with simple adhesive backed plastic sheet, I went the whole hog! Well, not quite as it's still a van with the wooden panelling inside still to maintain the privacy required. I did have the metal panelling cut out so if, at some point in time, I or the next owner wishes to take it a step further then it should be plain sailing. I've informed my insurers fully of the changes and was pleasantly surprised to find that, as it was still blacked out as a van, then there would be no increase in premium. Have to confess that I still have to advise the correct authorities of the same. So must make this a priority. I'll try to add a couple of photo's for you to assess the outcome. Oh, by the way the Windows were purchased from Vanpimps who were excellent with not only the supply but support also. Also, I engaged Car Glass and Trim of Ipswich to complete the work for me, having chickened out of attacking my two year old van with a tin opener myself! Couldn't fault either company for their professionalism.
Anyway thanks once again to you all and apologies if the title "Fake windows" turned out, unintentionally, to be misleading in any way!