Mavic Rush, around your budget – £99 or less. Excellent sole unit – Salomon Contagrip rubber = plenty of grip off the bike, unlike others’ hard plastic Teflon/ice soles; threaded for toe studs if needed; stiff enough for occasional racing but enough flex for hike-a-bike.
Got a 2011 pair that have been used for everything from CX racing, including running the length of Whernside in them at last years’ 3 Peaks, to all day XC rides, to trail bashing.
Lake MTB shoes, although harder to find in the shops, come up well in reviews too – the (Vibram) sole unit is similarly grippy with a decent balance between stiffness and flex. Reviewed in an STW issue about a year ago IIRC, might have been the MX236 or something like that.