Ok, i done the job,
lifted and the underlay was soiled with oil , nothing in the sub flooring , i cleaned the underlay with prochem fibredri, not brilliant as was expected . I then prespayed carpet back with powerburst , dwell for about 15 mins and extracted , was amazed how much oil was been removed.
Before relaying the carpet i cover the area of underlay with plastic sheet to prevent any thing else been absorbed by the carpet itself, now wether this is detrimental in any way to the carpet or underlay , i do not know !!! but seemed like a solution.
I then pre sprayed carpet after relaying again, power burst , hot dwelled and extracted ,again great result, plenty of drying stokes, blowers on to dry. cover the area in fibredri ,rubbed in with multiwash and left for an hour,vaccumed and hopefuly will have sorted the problem .It did look visably good on leaving , however i have left the custy with fibredri and suggested he cleans the area over the next few days as a precaution.
I hold my breath !!!!
Geoff