Karate Championships - Sponsorship??

Asking the meter manufacturers sounds like a great idea, it would be good advertising for them, and the worst that can happen is that they say no! You could ask whoever makes your insulin too - I don't know if you'd be successful as they don't really need to advertise, but again it can't hurt to ask.

As well as meters and insulin manufacturers (Novo Nordisk is a Danish company), it's always worth trying companies to ask for help in kind eg airlines for free flights, insurance companies for free or reduced price insurance, hotels for accommodation. But times are tight at present, so it's tough for everyone. Also, try Danish companies that market products in the UK eg Lego, Danish bacon etc. Worth asking for products that you can raffle, but be aware of regulations for selling raffle tickets, which vary depending on where you live.
Also, research grant making trusts - local library should have a copy - some have very specific geographical / occupational etc requirements.