Delivery versus in-house: What’s the difference in price?

I had a Deliveroo from Pho the other day. As nice as the Vietnamese curry always is, I was charged £11.25 for a dish that costs £10.50 in their Guildford restaurant. This started a small chain reaction of looking at other Pho price differentials, and then a few other restaurant chains. At Pho, the use of higher prices on Deliveroo was pretty much universal. Starter prices were typically 20p-30p dearer on dishes that mainly range between £4.95-£6.95, equating to a 4-6% premium on delivery.