That's even better Chris, ;east you shouldn't have to worry about it for a considerable time. Is there any form of heating in the upper part of the building? If it's been left empty for that length of time & there is no evidence of damp on the workshop walls then there is a good bet that some sort of damp proof course has been fitted. If the original conversion was for any form of dwelling then it would have been required from what I understand. Don't know if commercial type buildings or offices are the same though.
Is that 2 walls that stick out into the floor space & where is the access to the upper floor.