After searching the forum I've managed to find a way to get rid of the irritating shading of hyperlinks by selecting 'white' as the field shading colour. However, while this overcomes the problem in cells that have a white background colour anyway, the downside is that cells with an individual fill colour now have hyperlinks shaded in white.
Judging by the number of results I got when 'Googling' for a fix to this I would suggest that a lot of people find this issue rather annoying, so I'd like to suggest that a future update might include the addition of a 'no colour' option in the Field Shadings colour selection menu of the Tools>Options>Appearance section. Regards Andrew Shearer