Just check first that you can accept it because they may be restricting the amount you can do, (just realizsed your first... will be fine, check you can accept any further ones after first)myself and some mates that do tasks are all blocked from booking more... So... yeah, i have done mine that way, sit outside (if poss) and start to do it, answer all the questions you can, then go in, speak to staff, and fill rest in and take the pic, just be sure to spend MINIMUM 10 minutes in or very near the store. (BTW still showing on my app as £15?)