could give it a try make sure you layer in in between a few sheets of bleach free paper. or you could pop it in a Tupperware type box and try freezing it - this was v trendy about 10 y ago to do to your wedding bouquet.
What a coincidence, alba. I was just trying to find out where I could buy silica gel and came upon this site. I realize that it's a Canadian one; however, I'm sure you would have the same product in the UK.
http://www.leevalley.com/en/garden/page.aspx?p=48083&cat=2,50560
I used to do a lot of flower pressing in my younger days. I had several flower presses and used to make pictures with the pressed flowers.
One of my Aunts still has the picture I made for her, forty years ago.
You can just use ordinary kitchen towel if you don't want to go to any expense. Place the tulip flower and stem on the paper, fold the paper over it and put it in or under the heaviest book you can find.