Col,
amp doesn't make this connector in a 10 way...
I've looked at their catalogue and they only go up to 6 way.
Are you sure it is an superseal variety, and not something different ?
http://www.tycoelectronics.com/catalog/menu/en/10238 I usually get my connectors from RS (if in a hurry as they aren't cheap),
www.vehicle-wiring-products.eu (most of the time),
www.autosparks.co.uk,
http://www.autoelectrics.net/wiring.html,
http://www.autoelectricsupplies.co.uk (second choice).
Hope that helps.