Do you mean as an alternative to Ebay or FB etc. or to Hattons?
On my original question I note that it has been viewed by over 200 people at the time of posting and nobody had responded which is interesting as it suggests it's not so simple. By accident I found the answer this morning as follows.
First you must be logged in to your account, then select an item of interest and open up the detail, then click on the Green watch icon.
If you then go to My Account and go to Bidding on the listing on the left of the page, then click on Watching and you list of selected items is displayed. Another option is if you hover your cursor over the Watch icon on the item and it will display an option to go to the watch list.
It's not exactly user friendly and I think it would be better if the main menu offered the display Watch list as one of the search options.