(ShareCast News) - AIM-listed Bilby has downgraded its expectations for the year to the end of March 2017.Bilby said that one of its "long-standing and major public sector" customers has changed the way in which it manages its outsourced building services work, resulting in delays to expected work and some work being taken in-house by the customer.As a result of this and certain other additional costs incurred in the first half, it revised its financial expectations.The group now expects revenue to be around 10% lower than previously guided and earnings before interest, taxes, depreciation and amortisation to be approximately 25% lower.On a brighter note, Bilby, which is the holding company for a group of companies that provide gas heating, electrical and building services, said the businesses acquired since the financial year-end have continued to trade ahead of expectations.Spokemead and DCB have both met their earn-out performance conditions for the periods to 30 June 2016 and 31 March 2016 respectively and Bilby said the integration of these businesses is now largely complete."The board continues to strongly believe that the opportunities for the Bilby Group in social housing remain very strong especially in its targeted geographical locations, namely London and South East England."This confidence is underpinned by newly awarded contracts throughout the group that continue to extend Bilby's range of services and client base, firmly establishing its building services division alongside the market-leading gas, plumbing and drainage services on which the business was founded."At 1025 GMT, Bilby shares were down 17.5% to 66p.