Wheel bearing for self propelled Champion Mower?

I have a Champion self propelled lawn mower, probably 8-10 years old purchased from B&Q. The front wheel bearing has collapsed and I'm wondering where I might source one (or probably a pair actually). It looks like a bearing stuck onto a shaft that has a groove and circlip on the end of the shaft to secure it to the mover deck. If anyone had any idea please I'd be eternally grateful.