Good playpens for Syrian Hamsters?

Hi, I was wondering if anyone knew of good playpens for a Syrian hamster?

I’ve had a hamster for a couple months now, and I try to do free roaming with him, but the issue is he is always looking for escape routes, and he also tries to squirm into impossible to reach areas, (he has climbed into the radiator twice now… even when it was blocked off) so I’d like to get him a playpen, any recommendations? (If in store, preferably UK)

Thanks!