I believe Griots can ship internationally, definitely worth checking. Buy a gallon and their spray bottle, it goes quick! 20 ounces will cover the wheel wells and leave enough for future touch up unless you drive the car in rain regularly. 1 Gallon should last a 1.5 years if the car is a weekend toy only.
If you do decide to buy I also highly recommend their leather conditioner, it smells great and leaves a natural conditioned surface.
There's nothing quite like the Griots Undercarriage Spray however there are a few products that provide similar finishes. I would check with your local motorcycle shop for products such as Pigspit, S100 and other all purpose sprays which can be used on most surfaces. These sprays are usually aerosol and are designed to improve the appearance and protect most plastic, metal and rubber surfaces. I use Pigspit in my engine bay on painted, metal and smooth plastic surfaces. I also used it in the wheel wells on rubber surfaces. I wish I could help you further but I'm not as familiar with products available overseas.