my steering rack is pretty sludgy, chances are if its not dripping fluid then its probably alright,
the sludge has probably accumulated from years of driving on the road, small amounts of oil that seeps out from the seals, oil left on the sump from oil changes combined with abit of dust, that has made its way to the rack ,
take your car down your nearest clean park and give it a blast with the engine wash (i'd do it after the MOT encase there is a leak lol, even then you'll probably only get an advisory)

obviously i haven't seen it so i can only assume from your symptoms that its the same as other cars i have seen
maybe a pic might clear things up ?