I think I would try something closer to this.
With Marris Otter you are going to have plenty of backbone to the malt profile. I wouldn't normally use much munich if any when using a high quality base malt. I also try to keep my base malt above 65% of the mash to ensure plenty of enzymes available to mash the specialty malts.
Cara-pils is not very fermentable. I would avoid using very much in any one beer. If you want more body and head retention you can generally fine tune the mash to achieve this.
Most of the malts you have selected are very similar in Lovibond, ie: crystal 10 and Munich, Victory and Biscuit, I would tend to select malts with a wider range of Lovibond or not bother with making the recipe more complicated.
The recipe I have below is more of an American Style Barleywine...With relatively low bitterness.
14.5 # marris otter
2 # Munich 10L
1# Biscuit 25 L
1# crystal 40 L
.5 # carapils
.5 # toasted malt
I would move the boil to a 90 minute to make sure you actually condense the wort engough to get near 1.12. If you move the 60 and 40 minute additions of hop to there you would end up with about 76 IBU. I think that would work for a slightly sweet balance.
I would consider increasing the late kettle hops though. With that much grain the hop flavor may tend to hide. I would consider an additional oz of centennial @ 5 minutes or doubling the galaxy @ 5 minutes