[mumofstig]

I ordered a collection of Lavender 'plug plants', they arrived this morning.
I was astonished at how small they were 
The size wasn't indicated in the description, but these were only about 1.5cm across  I've never had plugs as small as this delivered before 
I've moved them up into the 'normal' size plug trays, for now, to grow on in the greenhouse, and hoping for the best....

[New shoot]

That really is a bit mean.  You would expect a plug plant to at least cover the top of the module with foliage.  Who did you get them from?  They might have a size guide in their catalogue or on their website somewhere. 

[mumofstig]

I had a look on Suttons site and found this, which I obviously hadn't seen before.
https://www.suttons.co.uk/plant-sizes
3 - 6 cm! Mine were on the lower end of that range...

[New shoot]

I would say what they call postiplugs are what most people would call a plug plant and what they call a plug plant is really a micro-plug.

Creative marketing at work there 

I used to buy quite a bit from Suttons, but had a couple of awful deliveries from them a few years ago and even worse customer service when I asked for a refund.  I hope your lavenders do well and/or things have improved their end if they don’t