Source: p 39, The Law of Contract, 5 ed (2012), by O’Sullivan and Hilliard
2.83. ... We have seen that the general rule is that displaying goods in shops only constitutes an invitation to treat, although there are good reasons for taking a diff erent approach (paras 2.22–2.23). However, what of a typical website that allows the customer to select the item, enter his payment details and seemingly conclude the agreement online. In this situation, then (absent the terms and conditions of the site providing to the contrary) it is suggested that it is clear that a contract has been concluded ... The natural inference is that
a deal has been concluded, as where you get through the checkout at a supermarket and have paid for the goods. You would not expect in these circumstances for the seller to be able to pull out.
What are the similarities and differences? Why not as when? The relative adverb modifies [the exact time that] 'a deal has been concluded', which is NOT 'a place, location, or space' as required below?