They've survived longer than I expected. They've struggled for at least two decades and I see that I predicted their demise on AB all of seven years ago:
https://www.theanswerbank.co.uk/ChatterBank/Question1197016.html
The Mothercare store in Ipswich is on the same retail park where Toys R Us used to be and, just like that other failed company, vastly too big to be profitable. (It's firms like Smyth's Toys and Richer Sounds, where they cram their stock into every corner of small stores, that stand the best chance of survival).