Limited Company - Transfer of Ownership

Futher to a recent post please can you confirm that my understanding is correct:

My client owned 30% shares in Company A Ltd and Company B 70% together they ran Company C Ltd. On 30/11/11 company B transferred the 70% of shares to Company A (my client Company A Ltd now holds 100%) at zero cost as the company had no assets on its balance sheet and had only be trading for less than six months.

From 1/12/11 to 30/3/12 Company A traded using the bank account of Company C and some invoices where issued using Company C’s details.

Prepare accounts for Company C at 30/11/11and prepare Company A accounts from 1/12/11 even though they were using Company C’s bank account and invoicing under the name of Company A & C. Should I re issue all invoices in the name of Company A?

VAT – Complete Company C VAT to 30/11/11 and re issue invoices with Company A’s details from 1/12/11, complete Company A return from 1/12/11

Again I would very much appreciate your thoughts on this.

Thank you in advance