Tom wrote:

I cant work out if it's classed as a HMO (House in Multiple Occupancy)
or not, there are 3 self contained flats.

This is probably more relevent -
URL:http://www.odpm.gov.uk/index.asp?id=1151996
The person to get confirmation from (in writing!) is the Housing
Officer at the county council who deal and advise on all types of
housing.

"If the block is a house which has been converted entirely into
self-contained flats the conversion will be regarded by local housing
authorities as an HMO if it does not comply at least with the standards
of the 1991 Building Regulations and if more than one third of the
flats are let out on short leases. These blocks of flats will not be
subject to mandatory HMO licensing although the local housing authority
may introduce additional licensing to cover them."

URL:http://www.odpm.gov.uk/index.asp?id=1163883&cat=100022#acat