Smeg SUK60MFX Dual Fuel Cooker

Hello,
I have just purchased a second hand SUK60MFX cooker and was told it was in good working order (at least it was 5 weeks ago before they moved house)

A British gas engineer connected the gas supply to the hob no problem and this is working fine.

However, when I put the plug into the electric socket for the oven/grill it immediately trips the main switch on the fuse box

Do you have any idea why this may be or what i should check/do?

Thanks