Best things I can think of are to use either the Black & White brush effect or the Saturation brush effect (at or near -100%). Both are accessed by tapping and holding the active tool in the toolbar to the left, then swiping down to the set of paint tools > Effects Paint Tool. (You can then select the type of effect you want to paint by tapping the active effect.)
Be sure to use a soft-edged, small brush (depending on how bad the red eye is). Pinch zoom if you have to. Usually, you should only have to paint the red in the affected pupil.
Many thanks this helps, although it beggers belief they dont have a better option
In addition to Warunicorn's helpful forum post, I have assembled a quick tutorial on how to remove redeye quite quickly.
1. Below is an image with red eye
2. Select the paint with effects tool. Select the effect, and select Black and White.
3. Adjust the size of the brush to make it the size of the eye.
4. Zoom into the image, and start to remove the red eye.
5. Now you have quickly removed the red eye!
Please ask if you have any questions