UK or French bank account for French registered business?

My wife has been an auto-entrepreneur since September 2014 and we understand that she is now required to open a bank account exclusively for her gite business in France. She does have a UK personal bank account in just her name which used to be used for her previous UK employment and daily living expenses before we moved to France in 2014. We also have both UK and French joint bank accounts. She needs to know the best way to set up a bank account solely for the auto-entrepreneur business, especially considering that many of the payments are likely to be in sterling and made in the UK.

1. Can she use her existing sole UK personal account from this point forward to receive payments from UK customers and rely on this as the sole account for the auto-entrepreneur income?
2. Alternatively, or even additionally, does she need to open a new French account to receive any income paid into any UK bank account? If this is the case then does it matter which UK bank account is used, i.e. her sole account or the joint UK account?
3. We understand the need to record the exchange rate on the date of payments being received in sterling, but if money is paid into a UK account then does it matter when or even if it is ever transferred into euros in a French account so long as the correct value on the date of receipt is shown?