Company enquiry, Directors bank statements requested

Limited company, selected for an enquiry, (2008 year end)

HMRC asked for a meeting which was attended and then issued a letter asking for accounting book and records. After their review of the records they then asked numerous other questions but also asked for copies of the directors personal bank statements from 2005 to 2009 or for them to sign mandates so hmrc could request them from the bank.

We answered the queries hmrc raised but asked them to reconsider if they really needed the bank statements in light of the information provided in that letter. 

The 'tax specialist' at HMRC has now replied stating they beleive there are cash sales undisclosed in the accounts (client is adamant there are none) and quoted various sections of the enquiry manuals and has reiterated that the bank statements need to be sent in or they will obtain them formally.

2 questions really -

Firstly, is this normal procedure to ask for these personal documents so early in the enquiry?

secondly, is it reasonable to ask for directors bank statements for periods prior to the year under enquiry for the company? Anyone got experience of this as the questions/answers from HMRC seem to be standard responses.