Hi Holly, Thank you for your enquiry. The mattress required for the guest underbed is W75cm x L180cm x H17cm, the suitable mattress we sell is the compact single Europa comfort guest slimline mattress which can be found on the link below: https://www.time4sleep.co.uk/products/europa-comfort-guest-slimline-mattress-compact-single Kind regards Laura

From the Time4Sleep team

The trundle bed can be completely removed if you are wanting to use the bed in a different room or location

From the Time4Sleep team