I posted not long ago asking the very same question, and was recommended Boots' Ultra Thin Breastpads, and Tommee Tippee's Breastpads. I bought Boots' first which were great so never bothered with Tommee Tippee's as they were slightly more expensive and I didn't see the need if Boots' were ok. At the same time as buying Boots' Ultra Thin BPs, I also bought a box of Boots' Super Absorbant BPs. Those were the itchiest, most uncomfortable lumpy things EVER!
Now that i'm only BFding Harry in the evenings I can get away with ASDA's own make which are the next best thing in my opinion. Better than Johnsons I thought.