Crosers,
Gardening Which tested composts last year and recommend New Horizon Organic & Peat Free Growbags (same as the New Horizon Peat Free Compost but works out 1p per litre cheaper) it still comes in at 5.7p a litre. (it was called J Arthur Bowers)
B&Q own brand Organic Peat-Free did not much worse and is only 3.6p/litre (when bought as a grow bag)
But no peat-free composts did well as seed compost
Phil