OP, I've recently completed my second stint of jury service - July/August this year. I think you would have a strong reason to defer if your DP doesn't receive payment from his employer and the expenses only would seriously impact you as a family.
I deferred initially because we have an adult DD with severe learning difficulties who lives in her own apartment in a managed centre close to home and the date allocated was very inconvenient for our visits with DD.
There was no issue with deferring! I just had to give 3 preferred dates over the next 12 months and they just came back with my second choice date. I heard of others being totally excused purely for financial reasons but worse case scenario you should certainly be able to defer to a time within the next twelve months which could prove a little easier. You just complete the form to request deferment which should be included with your original summons.
With regards to the expenses, you can't put in a claim until your jury service is completed - except in very exceptional circumstances/very long trial - and, certainly, in my experience, it took almost 8 weeks to be paid in full.😡. Fortunately, I could afford to wait but it was seriously annoying and I could easily see how some people would suffer severe difficulties waiting to be paid.
Yes it is roughly £65 per day to cover employment plus £5.70 per day lunch allowance for which you don't need receipts. You do need receipts for everything else and are expected to use the cheapest form of transport.🙄 I spent close to £100 of my own money just on travel and had to wait 8 weeks to receive that despite the paperwork stating 7-10 days from submitting receipts. 🤬
Honestly, seriously try to be excused or defer as I can well understand how you feel at present. People are excused for far lesser reasons. Good luck!