Scotchlite 280 is a produce made exclusively for Gerber/Spandex by 3M.
If you must have 280, then your only option (apart from waiting for Spandex) is to contact one of Gerber’s US distributors to see if they have stock. This might prove expensive…. You’ll find details of distributors on the Gerber Scientific Products website.
If it’s just a 3M 280-type product that you need, then one option might be to point out to Spandex that they could buy a roll of a similar product (Scotchlite 580?) from 3M UK, slit and punch and supply you, and others who are also no doubt waiting. There will be differences which might or might not matter – 280 cuts and weeds very well at small sizes and the 280i variant prints well on the Gerber Edge.
Hope that this helps.