Are identical looking mattresses from 2 outlets likely to be the same mattress?

RS2OOO

After a lot of searching we found our ideal mattress in a regional chain store (Sussex Beds) but somewhat over budget at £1500. 

For the following year I monitored the price and missed out when it dropped to £1100 in a sale and now its in another even bigger sale.... At almost £1800.

Before completely giving up I did a Google image search and found what appears to be the exact same mattress visually, complete with identical description in an online bed shop for £680.

Both mattresses have completely different names.

Could someone knowledgeable in this area advise how likely is it that this £1100 cheaper mattress is indeed the exact same mattress?

If you need more info or links I'm happy to post them, just wasn't sure if it was allowed under forum rules.