You're making massive assumptions here.
DH works as a prescribing clinician; he has been employed by his employer for long enough to know, having experienced what he regarded as an actual family emergency (sudden deterioration and ultimately death of a grandparent), that his employer categorically do not allow for short notice leave requests.
And great, so he takes all three of his EDL days in one go which will cover maybe 30% of the necessary days (still leaving 70% with no option). Then what happens if I become too unwell to look after our child in the next 12 months? You're being absolutely ludicrous if you think we should forgo any contingency plans for life happening simply to accommodate one stint of jury service that, it seems there should be grounds for me to at the very least defer.
And they don't live "100" miles away. I said "hundreds". One lives in Somerset, the other on the east coast; whereas I live in the NW. I have obviously spoken to them about the situation I'm in and neither have offered to assist. This means that they don't want to, presumably because they don't feel it's justified, and I'm not about to pressurise them given that it'd not just be a huge round trip (potentially twice), but they too would have to attempt to negotiate leave at short notice and find alternative arrangements for their caring responsibilities.
I've already stated that there is categorically no way I am willing to dump my child on the first qualified strangers I can find, in an unfamiliar environment, with zero preparation, for over 8 hours a day (given commuting to and from the court). Nothing to do with the money, everything to do with my responsibility as a parent to do what's right by my child, and that certainly isn't it.
I'm guessing you missed the part where I wrote I was actually pleased to get called up in the first instance?