You could try entering your requirements in one of 'used parts finder' web sites.
Typically these are free for buyers. . Car dismantlers throughout the country who happen to have a grey 2008 Jazz in their yard will be happy to sell a door that would otherwise just be crushed for its scrap metal value. They have experience sending large parts by specialist couriers at reasonable cost. You may get more than one offer. You may be able to pay through the sites own secure payment system, a bit like ebay.
You could try local scrap dealers but you will probably have more chance finding a grey Jazz door at a competitive price through one of these sites.
Here is one example, but there are others .(You could try more than one)
https://www.partsgateway.co.uk/A couple of practical points. One dealer may offer a complete door including glass, inner trim, electric window motors etc. Others may be stripped down just to the metalwork and this will involve a lot of work transferring over parts from your existing door. (Also you might be able to recoup some of your costs by stripping down the old door components and selling these bits yourself on ebay etc ) .
I dont want to put you off but there may be more work and complications than you realise in fitting a replacement door. . The Hinges may be damaged or the door post where they attach may have been deformed by the impact and things wont align properly. Or hinge bolts may shear off. But if you do acquire a door and then find some extra work is required thats beyond your ability you may find a small bodyshop happy to fit the door you supply ,and do a bit of body realignments etc as a quick job when they have free periods between larger projects. Especially if you are paying in cash . Good luck
