GovTracker will consider 'those who find it difficult' as those who would generally also fall under the remit of tax-free childcare.
The Government has established a program of 30 hours free childcare with very similar criteria to those which determine whether someone is eligible to recieve tax-free childcare. As a result, GovTracker has marked this promise as 'completed'.
Category: Social and Welfare
Source: Manifesto - Page 72
Reference 1: Gov.UK Childcare Page