Prescribe information

Possession - Section 8 and Section 21

our tenant is in arrears of 7 months rent and although she is getting housing benefits from council and Universal tax credit as well. She is keeping 2 men and 2 women in 2 bedroom flat whereas she herself also has 3 children ages 3,2 and 1.
The property is overcrowded and she does not attend our calls to discuss rent arrears.
We are trying to give her section 8 notice but our solicitor is saying that the Prescribed information by NLA on the second page of Deposit Protection Certificate is not good enough and there has to be a separate page of Prescribed information with name of land-lord and name of tenant should be mentioned on it.
We are with NLA for the last 8 years and with RLA for the last 4 years and never had any Prescribed information sheet with name of tenant and land-lord on it.
Our solicitor is saying that in the absence of this named Prescribed information, we will not have success in getting the section 8 in our favour and the tenant solicitor might claim on us for 3 times of the deposit if we did not have the Prescribed Information with our name and tenant name on it.
Could you please confirm if the solicitor is correct as we are in extremely desperate condition due to not having rent for 7 months and paying mortgages as well as the service charges and ground rents.
Kind regards
IQBAL SHEHZAD