They are a popular dish, so supermarkets usually carry several "grades" of kiev.
Here is the Tesco range...
I buy these ones:
http://www.tesco.com/groceries/Produ.../?id=264567646
They are whole breast (but filleted), not reconstituted. The chicken has taste and the garlic butter is ample. 62%.
Note that Tesco's do a more basic one than the above, which is reconstituted meat - this is the one that comes in additional "flavours" (viz: creamy peppercorn, creamy garlic, reduced fat, free range, cheese and bacon, and, briefly (seem to have gone now) cheese and onion). 56%.
They also do two "Everyday Value" types, one fresh, one frozen (the price is significantly different for some reason). Both of these are reconstituted, too. 46% and n/a.
Then there is a Finest one, which is bones left in (I don't like bones, so never had it). 75% (but does the weight include the bones?)
They also do a packet-of-four frozen offering. I haven't had these, but the price-per-pound seems to indicate these are near the Everyday Value ones in quality. n/a.