The public sector is obliged to follow specific rules for different contract types.
Large contracts must be advertised on The Official Journal for the EU (OJEU)
Although small contracts are not advertised on OJEU, purchasers are obliged to advertise them publicy (e.g. on websites) so all relevant suppliers are given an opportunity to apply.
As a member of Constructionline you will be able to search for both types on the Constructionline Opportunities Notice Board.
Other places to look for work opportunities include:
Look for supplier open days and meet the buyer events in council newsletters, websites and local papers in addition to the Constructionline website.