After some questions on the Internet I found the lower seat belt holes, under the fibreglass floor! the bolts will need to be 'spaced' to accomodate the carpet so that's a job for a bit later.

The radiator has been refitted and bolted into place along with the horns, and no they don't sound like the Dukes of Hazard as someone already asked asked.

I have some earth cables to attach and then maybe the engine can go back in.