Bonjour from Hawaii - they have lovely coconuts here

It seems that different Land Registry offices are operating the system in different ways. It seems that Larnaca want two forms - one for each purchaser. Maybe someone who has applied in Paphos can answer this for you?
You must take ORIGINAL documents and a copy for the application (two copies if Paphos LR also want two forms.)
They shouldn't need the Contract of Sale, but I suggest that you take this along with you together with your passports (and a copy of the relevant page).
Note that the 'Registered Contract of Sale No' on the form is the number written on the receipt from the LR when your Contract of Sale was deposited.
Regards,