Have you tried looking on DisneyStore.com, eBay, and Amazon? Also the parks shopping app? Without a more detailed description, it really is difficult to help since there is so much parks merchandise out there.
If you are willing to pay the high (usually) shipping costs, there are personal Disneyland shoppers who may be able to help you. A Google search should come up with some names.
Call Disneyland DileavEARS. You can get ANYTHING that is sold at the resort shipped to you directly from Disneyland. I don't have the number but I'm sure you can find it on Disneylands web site.
The OP is in the UK, so I'm not sure if a phone call to Merchandise Guest Services (Delivears new name) will work. Also not sure if MGS ships internationally. I've heard that the shipping costs are high even for domestic packages, so it shouldn't be that different to go with a personal shopper.
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