Can you recommend a mattress topper for a bad (lower) back please?

[AnnaNimmity]

I've recently splashed out on a new mattress and it's giving me really bad lower back pain! I swapped it under the manufacturers guarantee for a different one, and that's giving me problems too.

I can't swap it again, and don't want to replace it (it was VERY expensive) - can anyone recommend a good mattress topper for bad backs? I can't sleep on memory foam as it makes me too hot

Honestly, I should have stuck with my cheap Warren Evans mattress!

Thanks.

bumpety bump

I got one from Dunelm, but can't remember what weight or thickness it was. Made an lot of difference to a too firm mattress.