compost vs topsoil at Wilkinsons

Last year I ordered some compost from Wilkinson (50l per bag). Now I see they also sell "topsoil" for a terrible price http://www.wilkinsonplus.com/invt/0261821 vs http://www.wilkinsonplus.com/invt/rw00003. What is the difference? I need about 5cm coverage on 3x4m area, please advice what to order. *clueless*

 

Compost is "like peat"

Top Soil if just soil - but good quality.

If you are top dressing around your plants sounds like you are looking for some "humus" to provide water retention and improve the health of you soil, so you are looking for Garden compost, Well rotted manure, Mushroom compost, Spent hops, or something like that, and what the garden centres call "Compost" will do well - but its an expensive way of buying it

3m x 4m x 5cm is about 600 litres. A bulk builders bag is closer to 1,000 litres - might be worth considering one of those as I expect it would be cheaper, but I'm not sure you can buy ordinary compost that way. Actually your second link, to Rolawn Topsoil) is a Builders Bag - and FWIW Rolawn is a very good brand. But I don't think top soil is what you are after.

P.S. Well what do you know! First result in Google was for bulk bags of compost. Works out at about £100 for 1,000 Litres. The "Wilko Forest Gold Plus Compost Multi Purpose 50ltr" would be about £80 for 1,000 Litres - so looks like buying it as-needed from Wilko will be cheaper.