What I want is this:
RowID, 1stAddr1, 1stAddr2, 1stAddr3, 1stAddr4, 1stPostcode, 2ndAddr1, 2ndAddr2, 2ndAddr3 (etc)
If you need just two columns: RowId and ConcatenatedAddress - use advised FOR XML with STUFF thingy.
If you really want what you have asked - pivotted multiple address columns - you need dynamic cross-tab. Here the one from J.Moden to help: