Question about rent arrears and guarantors responsibility of payment

Tenancy Deposits

Dear Sir/Madam,

In one of my rented properties there has been a marriage break up and the husband left the property in May this year. The wife is in arrears. The husbands mother acted and signed as guarantor on the RLA deed of guarantee (Signed and witnessed).

I have approached the mother for these arrears. She has stated that she has consulted solicitors and that as her son left the above property she is refusing to pay the arrears. The mother did notify me by letter a month later that her son had left and as far as she was concerned she no longer wanted to be guarantor.

Notice Section 21B had been issued at the beginning of the Tenancy (ending on 26th August 2008). If I issue court proceedings can these court costs be added to the rent arrrears. Also is the mother liable for these arrears and costs as hopefully she is still gauarantor on the property?

Thankyou