Identify Please ?

 I have a tree / shrub growing in a container.  It's 3 foot high with an upward growing habit.  The leaf (above) is about 1 inch long by half inch wide.

Any suggestions please ?

I think we are going to need more than a leaf-can you take a picture of the whole plant-does it flower at all?

My first guess would be hibiscus/mallow/lavatera

Yep it looks the same as the leaves on my hibiscus

Sadly looks like my hibiscus too- any suggestions why leaves are yellowing? Considering digging it out- it flowers well but looks so sad.

I've had it for a few years now. Never seen any flowers.

I'll take another photo tomorrow.

Many thanks.

I have to say my hibiscus for the last few years looked sad. Leaves were pale looking. This year i just lopped about a foot off of it and ive been feeding it religiously with miracle grow, stuck a bit of mulch around it (its in a container). I have to say its looking really healthy now. Diggermum, maybe it would benefit from some sequestrene?