2005 Ford Mondeo steering knock

Hi, sorry to take up three sperate posts, but didn't think it right to post three questions in one post in case someone else is searching for similar issues.

Ok, the last issue, is when i first set off in my newly purchased, possibly a bit of a lemon, 2005 mondeo, for the first couple of minutes, the stearing wheel clicks a little, like its riding over a bit of a bump, when its turned in either direction from its central position. This only happens for a couple of minutes, then its fine but happens every time. I am expecting you to say Stearing Rack, but wondered why it would ease off after such a short period. I wondered if it might be the power stearing fluid or something like that?

Thanks Alot, again, sorry for flooding you board but times are tight at the moment and need to ensure money is spent wisely, so looking to you experts to give me some advice before i go get fleased by the local ford garage.

Thanks Alot Gents

Richard