Did bognor last year for 5 nights and you are very wise in only doing 2

Accomodation was fine, you pay for what you get so might be worth going gold, i was in silver though and was happy enough, I did self catering as these apartments give you more room than the half board, food used to be bad but people seem to like it now. Only thing was I found myself dropping a bomb in drinks, food and some activities.
Your DD will love the entertainment, Bob The Builder show about 5 times a day, mini fair rides inside the pavillion, trampolines, plenty of playgrounds, a pottery studio where she can paint her own, the central shows and story times, puppets, and of course the swimming pool.
So yeah if its a weekend then you and DD will have a great time and Bognor is a good site, watch out if you venture out to look at the sea (just across the road) as you could well get blown away
Oh yeah, I happened to work down at Bultins Bognor 10 years ago for a summer and even though it was work I still had a blast there