Check whether they actually need to be certified.

I just scanned copies of my certificates and passport and emailed across the .JPGs, I wasn't asked to get them certified.

If you definitely need to get them certified, as an Aus in London, do you not have any friends working for law firms, either as lawyers or secretarial/admin, either temp or perm? They have stamps saying something like 'I hereby certify this is a true copy of the original ...........' with a signature space.

If you do ask your friends to take your documents in to work, run them through the photocopier, ask a secretary for the rubber stamp, put it in front of a nice friendly lawyer (there are some!), say I have a friend who needs some copies certifying, and hey presto.

When I've worked for law firms in the past, I would have done that for a friend.