I recently bought an IKEA mattress, 140 x 200 cm. I need to buy a good
quality fitted bedsheet for this mattress.

I phoned Debenhams, and they said they did not supply this size, and
suggested a King size fitted bedsheet, 152 x 200 cm. This is not quite
what I want.

I could buy one from IKEA for 15 GBP. Frankly, I would like a more
expensive and better quality bedsheet.

Is it safe to buy the low priced one from IKEA? Is it right to reject
Debenhams which is the wrong size? Are there other retailers, online
or in real life, who could have a better product than IKEA?

tyvm