Welcome to GOY!!! I garden on heavy clay. It took me a few years to be able to get my garden in any kind of order. You will need a lot of organic matter dug into the soil, manure, compost and the like. I grow my veg in raised beds. Over the years the soil does improve. Clay soils are very fertile but compaction is a big problem. I was told once by a proffessional gardener to concrete the lot!!!! But I didn't as I'm sure my photos will prove this to you.

Thanks for that which is worth a try. Our problem is that clay is so wet we have a few inches of standing water across half the garden so feel we need to do something rather more immediate - if such a solution exists!
Brian

thats really bad drainage! the only permenant measure is to put in drainage pipes. spiking the lawn and filling the holes with sand will help and in flower beds as great has suggested, dig in lots of organic material. you could try some raised beds too. the problem with clay is that it will dry brick hard in the summer. If its a new house the builders will have compacted the soil