I just checked and the offer is still there.
On the homepage, underneath 'Latest Releases', click the 'Buy Now!' where you see the line 'Get 30% off YCBG when you buy YMHB in the same order! - Buy Now!'
You will then see both products appear totalling e.g. Eur 32.28 - Eur 18.99 for Hobart and Eur 13.29 for Cambridge.