Discovery assessment?

Had a letter frim HMRC saying and internal compliance review of 207-208 Partnership return shows a bigger profit that my clients return so a discovery assessment will follow.

Partnership is a film scheme LLP who sent a statement to client on 15/4/2008 showing tax return details (phip ret was subitted 31/1/2009). No further statement recived.

Can HMRC be making a discovery as they have had info for two years?