Finally got to the bottom of this telephone number- It was a great system and worked but the HMRC have removed that telephone number and you can no longer call direct to them. The on line INFO-
http://www.hmrc.gov.uk/budget2011/tiin6330.pdf
Their contact details are now a call centre here
HMRC Contact us
0845 010 9000 has to be the longest answer machine option I have heard, but the operator who answers is not attached to minerals oil relief so not much help
They advise to write direct to
Minerals Oil Relief Cntre
Benton Park View
Newcastle Upon Tyne
NE98 1ZZ