At the very least AOL customers must be connected to Talktalk kit in exchanges where AOL have no presence.
Yes, but in such exchanges where AOL is not LLU'ed (e.g. Wraysbury where I did my test) AOL will only offer you their Full LLU package of Broadband + Calls + Line Rental. Whereas in exchanges where AOL is LLU'ed (such as my Reading one) they will offer you their 'Up to 8 Meg' Partial LLU packages (for what is worth but will suit some).
So, in essence AOL may cover 85% of the UK with their, shared with TT, Full LLU product, but only about half that with their unique differentiated Partial LLU products.
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 20 Meg WBC