Callum, There is always a chance you wont see anything but Skye is good place to go as is Mull and the Outer Hebrides.
On Skye there is a visitors centre with information on the WT Eagle which will tell you where to go.
Mull is probably the better place to be certain and I have seen several on the Uists.
The Cotswold Water park sightings website
My Flicker page
CF, welcome to the forum! There are many RSPB blogs recently about the tracking of WTSE on Mull just google for links!
2013 photos & vids here
eff37 on Flickr
As Bob says Mull is the current "hot spot" for W.T.Eagles but we have had sightings off most of the North West coast of Scotland over recent years.If I was desperate to add the bird to my list Mull would be 1st choice as locals often run boat tours to see them during the summer months.
Pete
Birding is for everyone no matter how good or bad we are at it,enjoy it while you can