Should I put my unconditional offer as my Insurance just to be safe?

I have received offers from 4 out of my 5 uni choices. 3 of these are conditional offers and 1 is unconditional.

2 of my conditional offers are from sussex and goldsmiths and I would be very happy to go to either of these. My unconditional is from Portsmouth which I am still keen on but not as much. Would it be better to make this my insurance choice just to be safe or is it worth risking it and making my insurance choice a conditional offer aswell?

I have already done a btec for which I got DMM and am currently doing a foundation course which is what the conditions seem to be going on. The conditions say that I have to get a distinction in this, but do you think they would be more lenient if I dont get this as I have already got a fairly good grade at A Level?

Thanks