Reducing strictness of match to remove need to match previous address.

This helps for the stories regarding the start of conveyancer/citizen relationship.

When we integrate with IDA we need to revisit all of this anyway and at that time
I believe we'll have need some notion of confidence level for match?

So in short, please let's just allow this for now as we know it's a work in progress.
Merge pull request #3 from LandRegistry/relaxed-match

Reducing strictness of match to remove need to match previous address.