Can a grandparent who provided regular childcare before separation use that history to support a contact claim?

Yes, and this kind of history is often some of the strongest evidence a grandparent can bring to a contact application. Regular childcare - picking the child up from school, providing daytime care, being a consistent presence during the week - demonstrates exactly the kind of close, ongoing relationship the best-interests test looks for, since it shows the child relied on the grandparent in a real, practical way, not just as an occasional visitor.

To use this history effectively, gather whatever documentation exists: a record of the schedule you provided care under, communications with the parents arranging that care, and any evidence of your day-to-day involvement, such as school pickup logs, photos, or messages. This kind of history can also support an argument that losing contact represents a genuine loss for the child, not just for the grandparent, which is the framing that tends to carry the most weight with a court. Where the childcare arrangement stopped because of the separation itself, rather than any concern about the grandparent, that context is also worth explaining clearly, since it distinguishes the situation from one involving an actual safety or suitability concern.