Roof Bars or Rack

My Discovery 2, 2003, has the two standard roof rails and I've been looking at something to allow me to put ladders or timber, etc on the roof. I thought about those racks, but the only ones I can find are near to £1000!
Am I looking in the wrong places? Also, do these racks fit onto the roof guttering?
I then began looking for cross members and I can find no clear options for attaching such things to the standard rails, which seems odd.
So, my main question is, what is the use of the rails and what do people do (two questions perhaps)?
Do people just bodge their own cross members onto the rails, or are the rails just useless and do people buy independent cross member roof bars to attach onto the guttering?
Andrew

Hmm!
My D1 came with the detachable cross bars and I used them umpteen times for moving doors, ladders etc. Love em to bits.
D2 came with the bars but no cross bars and no holes to put em in! So didn't like that. Wondered if it was cos it has two sunroofs. So then took to using the sunroofs open for transporting long stuff, but couldn't get a door in that way!
I'd be tempted to buy some of those rails you can attach across a pair of bars, but that is all a bit of a pain.

I have Thule roof bars on my D1. I bought them from ebay IIRC I paid 80 quid for a pair, then picked up another pair for 50. Solid as a rock. The second pair, again if memory serves, came from a transit van that was being broken. So may be worth looking at van roof bars, could be cheaper.

I'm still struggling to find the roof bars that I'd like. Thule seem to do them but they are only two and these affix to the inbuilt rails. I wanted something that would extend down the full length of the roof. If someone knows where I could get these from then I'd be grateful.
I wonder, is it because the Discovery 2 roof guttering isn't strong enough to hold roof bars?