It begs the question - how did they make cottage gardens in the old days - they surely didn't have raised beds or anything modern and just broke the clay down in the old fashioned way - sheer hard work, manure and organic matter dug into the soil. Clay soil is full of nutrients and with a bit of work could make a beautiful cottage garden.

You'd also have to add tons of grit because most cottage garden plants like thin poorer soils.

My front garden is cottage garden style and the flowers grown there reflect that, if you read my profiles 'garden' section you'd see the plants there.

I guess you were told to raise the beds because of your clay? Unless you want a raised bed I wouldnt bother as a raised bed will not make it look cottagey and unless its deep the roots will still meet the clay!
I too have clay and having dug 2 spades deep I mixed grit and load of humus to improve the structure before planting my cottage garden. The more you prepare the site the better the end results. As well as soil type consider water and the amount of sun/wind the site gets.There are special seed packets for cottage gardens and lots for you to see on Goypeadia why not take a look?
It takes some years to achieve a cottage garden look, and get it to bloom from spring to autumn. When I first started mine I relied heavily on annuals to fill in the gaps till the plants grew and took up the space and sowing seed such as 'Love in a mist' was a real must.

Go with what Drc724 has said - mix in grit (builders sand) and humus (bark chippings) to two sades deep. That allows better drainage, allows plant roots to go deep and has started the process of breaking down the clay. I always put compost to a depth of about 2-3 inches to make the area look better and to allow sees to sow. You can always add some fine bark chippings around established plants.

Thankyou very much to everyone who answered my question..I am now on a mission :)

Do keep us posted Kate and good luck