lawn feed recommendations?

Hi all
Last autumn we seeded a new lawn and it took well and looked very green once it got going. We fertilised the ground before seeding and also gave it an autumn feed. However, as the grass is looking very yellow and is obviously in need of a real boost. We gave it some Homebase own brand weed and feed about three or four weeks ago but it hasn't had much effect. Can anyone recommend a really good fertiliser that will boost growth and "green" it up. Not sure whether 'weed and feed' is a good idea, so am happy to do some spot treatment of the weeds if necessary. Any help would be very welcome. The soil is of mixed quality, slightly towards claylike underneath - plus we imported two lots of top soil from different suppliers - so not sure how good it is nutritionally. Think all the rain we had in the autumn/winter has washed any goodness away.
Many thanks

Hi GG

Yes, it was a weed and feed we used from HB. There are a couple of areas which look a bit greener than others, but not by much. I've just taken a couple of piccies - see what you think ...

Thanks GG - will definitely get some feed on it, without the weed bit, and ask 'the boss' whether the blade needs sharpening - good thought. 

Don't forget to lime the lawn as well.

Hi fatcat1955 - what does the lime do and how do we apply it?

Lime enables plant's to take up nutrients thus ensuring you get the lush green growth you desire on your lawn. Do a soil test first then google for how much lime to add. It also will bring down the PH which should keep moss away too.

Sorry to disagree, fatcat, but lime raises the pH of the soil, not decreases it because it is alkaline in nature.