Levy Transfer insufficient funds in 26/27

I don't think the main Apps rules say either way. It just says:

248. For employers who either do not pay the levy or have exhausted the levy funds in their apprenticeship service account, then if at any point the ‘sending’ employer has insufficient funds to cover the cost of the apprenticeship training, the receiving employer will be liable to fund part of the remaining costs (see paragraph 214 for exemptions). The rate at which co-investment will need to be paid will depend on when the apprenticeship training started.

I agree you can infer that it would just be 5% because paragraph 213 says that, and why would the receiving employer inherit the characteristics of the sending employer? Especially when it's very clear the payment liability belongs with the receiving employer, so I would expect the normal non-levy rules to apply.

I don't think the unit rules are clear either. They say:

119. For employers who have exhausted the levy funds in their apprenticeship service account, then if at any point the ‘sending’ employer has insufficient funds to cover the cost of the apprenticeship unit, then the government will only fund 75% of the remaining payments (see paragraph 93 for more information).

120. For levy-paying employers, if at any point the ‘sending’ employer has insufficient funds to cover the cost of the apprenticeship unit and the receiving employer has sufficient levy funds available then these funds will automatically be used.

Both of those can only relate to levy-paying receiving employers, because a non-levy employer can't have exhausted their own levy. It just doesn't say anything about non-levy payers.

It definitely needs clarifying, and should absolutely match across both full apprenticeships and units. My approach would be to just wait until it happens and see what values appear in the co-investment report, but that's not useful if you're pre-emptively trying to detail this in a contract.