Hi I think they technically can count in ratio but NOT at the level they are studying - if studying for level 3 they will count as level 2 for ratios. For your 13 children you'd need minimum of a level 3 qualified member AND at least half of any other staff qualified at level 2. So if the level 3 and two apprentices are all you have then no I dont think it works. However since ratios apply across the whole setting not per room (which I've always struggled to understand!) if there are other level 3 staff in the setting it may be.
This is what I found on the kinderly website:
Students on long term placements and volunteers (aged 17 or over) and staff working as apprentices in early education (aged 16 or over) may be included in the (qualified) ratios at the level below their level of study, if the provider is satisfied that they are competent and responsible (3.49).
To assess competence, providers could use the criteria in Annexes C, D & E from the DfE Early years qualification requirements and standards to support them.
This change means that someone studying towards an approved level 3 qualification (including qualifications at levels 4, 5 and 6) may count within the level 2 ratio, and someone studying towards EYTS or QTS may count within the level 3 ratio.
For reference, not all level 6 degrees give a licence to practice. They must have been assessed in practice and be on the Early Years Qualifications List (EYQL), in which case they will count as level 3 for ratio purposes. To count as level 6 for ratio purposes someone must have EYTS, EYPS or QTS.