I spent this morning looking at the John Lewis website and spent ages trying to find out what the sleeve length is on their shirts.  I still can’t find the answer on their website, which gives you the collar lengths and the chest sizes here.  I went into the John Lewis store to ask and it turns out the John Lewis shirt sleeve lengths are all 34 inches for their standard shirts and 36 inches for the longer length sleeves.  They don’t vary the sleeve length for their shirts. Click on the image below to visit the John Lewis website.

Update – 3rd of December and still John Lewis don’t put this information on their website.  I can’t understand why they don’t sort this.
Updated 9th February 2016 and still this information isn’t on the website.