HELP! Homepage is ranking lower than a subpage!

[webthing]

Hi there,

Can anyone shed any light on this?

My clients website is no.3 on Google search in the UK when you search
for keyword "carrier bags" but the page that is being ranked at no.3
is http://www.aplexpress.co.uk/plastic-carrier-bags.html and not
http://www.aplexpress.co.uk/

We really want the homepage being ranked highest but cannot figure out
where we're going wrong. A while back the homepage was ranked in the
top 5 but since about 6 months ago it's dropped to around 19.

Any suggestions would be much appreciated.

Thanks

Chris