The engineer will probably only use what cables you already have, they won't supply any extra cables.
HDMI is by far the best way to connect (gawd knows where you looked that recommended SCART!)
On another note, Don't get fooled by any one that tries to sell you an expensive HDMI cable saying you will get a better picture, that is total rubbish, HDMI is a digital cable and you will get the same results using a tesco value cable (about £3) as you would with a monster cable (about £100). either buy them online (
http://www.amazon.co....qid=1258394640&sr=8-1 ) or as I did recently at your local large Tesco for under a fiver!
Note 2, if your TV is full 1080p HD then make sure you go into the settings for the sky box when you get it and turn the output to automatic (not 1080p) as this will improve the quality when viewing non-HD channels.