Hi Smiley
When my late mother went into residential care I rented out her house and insured it through a company called HomeLet (homelet.co.uk) who, as their name implies, specialise in this type of insurance. They were recommended to me by the letting agency who handled the letting.
Mike
ps I would recommend the use of an agent although it does cost a bit. They get financial references for prospective tenants, collect the rent, take care of repairs and electrical/gas certifications that are needed, inspect the property before, during and after each tenancy, etc.