This MAY be a valid manual:
http://www.belling.co.uk/media/62510/08%2027505%2002%20-%20Belling%20DFt%20ranges%2037.pdf
You may be able to find more here:
http://www.belling.co.uk/customer-care/manuals/
Alternatively find the exact model number and do a Google search for that and the word "manual"
XXX
December 2015