One thing that might help is if you explain that the only reason for your visit is that your fiancee is not yet free to marry and that you mearly wish to be able to spend some quality time together.
If you also explain that you intend to marry as soon as your fiancee is free to do so and that you are fully aware that if you were granted a visit visa and then breached the conditions of that visa, your chances of eventually being granted a settlement visa would be seriously jeopordised.
Iain.