Latesy update from Amazon regarding this problem.So now it appears they think I am outside of the UK. After several robochat calls 6 emails & 2 hours on the phone this is the answer I got from them today.
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Thank you for providing screenshot.
I am sorry to hear that you are facing issue in placing the order.
Firstly, please accept my sincere apologies for any inconvenience caused by this.
I'm sorry but we can't send Milwaukee 48-22-1934 Trapezoidal Blade Rounded Pack of 5 , Red to Northants, NNXX-XXX, United Kingdom. When you shop at Amazon from outside of mainland UK, messaging at checkout or on the product detail page will let you know whether an item can be delivered to you. To determine your location we'll use your default 1-Click delivery address when you're signed in to your account and 1-Click has been set up; otherwise, we'll use your IP address.
To add or change your default delivery address, go to "Manage Address Book" in the Your Account section of the website. Scroll down to the address you want to make default and click "Click here to make this your 1-Click default address".
Age-restricted bladed products can't be delivered outside mainland UK & Northern Ireland.
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They have however given me a £10 gift voucher to use on another purchase. 
So I really tried Ian but sorry looks like I cannot buy this for you. I have sent another email asking how they decided that I live elsewhere other than the UK. So I still live in hope. And no I do not run a VPN.
regards