Help gammon for dinner and forgot to put the slow cooker on!

[iamnotaponceyloudperson]

I haven't cooked gammon in the slow cooker before. Planned 7 hours on low for a 1.2 kg gammon. But forgot to switch it on. Do you think 1 hour on high followed by 3 hours on low would work?

I originally planned about 3-4 hours on high after 1 hour it already looks fairly cooked.

Any thoughts?

Am cooking on brown sugar if this affects anything.

Slice before serving and if it doesn't look cooked through give it a few minutes in the microwave.