Royal Exchange theatre, ManchesterSparring lovers play a capricious game in Blanche McIntyre's revival " but the cut and thrust is kept witty, rather than curdling into danger In director Blanche McIntyre's take on Private Lives, love is a dizzying thing. Staged in-the-round, Noël Coward's vicious comedy of desire and spite is spun around like the records its sparring lovers play on the gramophone. From the moment…