Hi FiL,

You add your HDRI as an "environment image" in the render settings. By default, Simlab Composer is probably already using the "Default.exr" image. You can replace whatever image Composer is using with another HDR image, such as the ones linked to. For Composer to use these HDRI's you need to ensure that the "environment image" check box is selected. Also, the HDR image can be used as a visible "back plate" for your render by selecting "back plate - from environment".

It might be worth you signing up to the Simlab forum. The support guys on there are very helpful.

Mark