TECH: problem with 'previous' button on top page bar of MN Classic

[LadyFoof]

What the title says really, sometimes on a multipage thread the arrow button for 'previous page' doesn't appear on the top bar. Example here

Not a big problem, just something I've noticed recently.

[HelenMumsnet]

Thanks, LadyFoof - I hadn't noticed that before.

Will see what can be done to fix it...