"Information - hearing aid batteries"

I sought simple information about how to obtain replacement batteries on behalf of my elderly mother, who is resident in Lyndhurst. Neither of us can use the telephone easily due to hearing impairment. It was impossible to find the information under any recognisable heading, although I know there is an audiology department at Lyndhurst N F Hospital. ENT is shown below, but we visited the Hearing Aid Department for reassessment of my mother's hearing.