Mayan -
I'm also a FindMyPast subscriber & while Ancestry's had the free access *(until early November IIRC) I've been looking for my missing. Some still are missing, but most of those I've found were ones where FindMyPast have used the same surname for everyone on the page - even the servants.
This sort of thing using made up names - "John Smith" a farm servant on the farm of the Johnson family would eventually be found to have been transcribed as John Johnson (though the schedule was clear as Smith). If "John Smith" had a relatively rare combination of first name, age and place of birth you could try searching on those three elements - I'd already found some that way.
Other things I've found on FindMyPast's 1911 is that they don't seem to have pigeon-holed place & county names in the same way as the earlier censuses, but have more exactly used what was written. Examples:
"Macclesfield, County of Chester" on census schedule - searches will find from Macclesfield or Chester, but not Cheshire
"Macclesfield" - searches will find from Macclesfield, but not Cheshire
* In case you've not tried - if you have an Ancestry sign in (eg from a former membership or free trial) you can use that, otherwise you will need to create one.
Good hunting!