I cannot recommend this Leyland Truguard Pliolite based masonry paint highly enough:
It fills in small surface cracks, keeps its colour and lasts several years in the wettest of weather conditions. It is available at Johnstone's Leyland Decorating Centres, see here:
Not only that, but I ordered some more yesterday afternoon from the Bristol (St Phillips) Decorating Centre and it was delivered free of charge this morning at 9am (Christmas Eve)!
3 hours ago