Our local farm shop have been free delivering , also taking their vans to hospital/ambulance and fire stations plus other key working areas for staff to buy from van.
Also the price & high quality has been maintained, we used to buy a few items from the farm when passing, now they are delivering all out fruit & veg are no supplied and there is a noticeable difference in the prodcut quality, this for me is key, as the quality is higher, i will continue to purchase from the farm shop locally after the lockdown is over, probably increasing my spend to them by 3 or 4 fold over before the lockdown.
and if they continue the delivery , then even more likely to continue 100%
I also like that if the wholesaler price goes to high, they won't buy and pass on , what they consider overpriced or exploting items, so they seem to be able to bring some pressure onto the wholesalers.
SO, for me Quality and good value for money is key. Free Delivery may play a part
You may want to look at the competition and see what they offer.
Friends of ours have bought into the box's of in season fruit & veg before the lockdown, and that has increased also increased amoungst friends and relatives. BUT I prefer to be able to email the list of what i specifically want.
good luck with the venture