Anyone know the name of this plant please ?

[lettuceleaf]

I believe leaves "breathe". Dust on the leaves would inhibit this. Therefore, Leaves should be kept clean
I'm sure someone who knows what they're talking about will be along soon

No-one came along, so I did a bit of research. Here follows a potted lesson on botany.

Plants do not breathe as such, they take in air through their stoma which are pores in their leaves. They photosynthesise and respire - respiration is not the same as breathing.

To photosynthesise, green plants absorb light energy from the sun using chlorophyll in their leaves, which produces chemical reactions for converting carbon-dioxide into oxygen and glucose to feed the plant. The glucose is used in respiration which is using oxygen to produce carbon-dioxide, or the glucose is converted into starch and stored.

Temperature, carbon dioxide concentration and light intensity are factors that can limit the rate of photosynthesis. I would add dusty leaves to this.

So, in short, Veggiechicken, you're right. It is essential to keep leaves dust-free for a plant to remain healthy and thrive.

[veggiechicken]

That's exactly what I meant but didn't want to use too many long words to confuse anyone (especially myself)
Have you managed to clean your leaves yet?

[lettuceleaf]

That's exactly what I meant but didn't want to use too many long words to confuse anyone (especially myself)
Have you managed to clean your leaves yet?

I believe you ! and I apologise for the long words but we got there in the end.

No, I haven't managed to clean the leaves. I've been waiting to put the plant out in the rain - but no rain. Not that I particularly want it, it's good to be able to get out into the garden at last. But rain has been threatened so my plant won't have to wait too long. Thanks for your help.