It does seem to have been a long time coming, I agree, almost to the point of feeling like vapourware, I too have read about Reaction Engines, Sabre and Skylon, for well over a decade, without seeing much progress.
However, I think that is probably due to a lack of funding, rather than issues with the underlying technology, and as we all know, trying to secure funding from the British government for any sort of technology that doesn't involve the BAE Systems pork barrel is doomed to failure.