Original: At Sheffield Archives, not all archive material is stored onsite and we may require notice of the items you wish to see.
Simplified: At Sheffield Archives, not all the archive documents are stored onsite and we may need notice of the items you wish to see
Simplified: At Sheffield Archives, not all archive material is stored onsite and you may need to ask before for items you wish to see.
Simplified: At Sheffield Archives, not all material is stored onsite and we may require notice of the items you wish to see.