Sofa bed bedding

[PGmicstand]

I've just ordered a sofabed which has a mattress that is a European double size (140x200cm), but thinner than a conventional mattress (12cm deep)

Any recommendations for suitable fitted sheets? All the ones I can find online that are the right size are "deep", whereas all the standard and shallow depth ones seem to be too small.

Am I overthinking it and is it the case that a standard double would fit?

Overthinking it. I use those stretchy ironing board cover clips across the corners on my futon sofabed. I use a deep double fitted sheet. They're hidden under the mattress, along with the extra flap of material.

I wouldn't have thought of those sort of clips! Shall go and investigate forthwith.