What will grow with my grapes???

Hi, I'm nearly finished building a pegola thingy. I've got a wall on one side and 3 posts on the other side with 5 beams going over to the top of the wall. I've bought 4 9ft Boskoop glory grape vines of which I have been assured 2 will grow happily up the same post so I can plant 2 on each of the end posts and train over the 2 beams on either side(if you know what I mean). Which leaves me with the post and beam in the middle. I would rather have a flowering climber for that one. Preferably one that grows quickly which will not hurt my grapes if it does reach them on the beams or below ground. In an ideal world it would also have white, long lasting flowers but then in an ideal world I'd also have won on the 3:10 at Goodwood! Is there such a climber or should I just stick another grape up there??
I haven't planted anything yet so if it makes a difference I could use an end post/beam if need be.
I was a tree surgeon for many years so I'm not completely devoid of gardening experience but I know very little about plants uses/situations so any help or advise would be greatly appreciated.
Thanks in advance

 

Grow and climber preferably one that attracts bees too