Spiced Scotch Ale with Prunes

[MillStBrews]

I'm planning on making a lightly spiced, strong-ish Scotch Ale this weekend using a kit as a base. I wanted to add a fruity depth with some prunes.

I am toying with ideas about how best to incorporate them - in a short boil, steeped and added to secondary or at racking stage. What to steep in. ie warm beer, sherry, marsala etc.
Any pointers from more experienced heads would be appreciated. I have researched already but can't decide on what is likely to give the best result. My planned ingredients are below.

Coopers dark ale kit
200g Caramalt steeped 80 deg 30 mins
100g Choc malt steeped 80 deg 30 mins
40g Challenger pellets steeped with grain
1kg Medium Spraymalt
150g Musacvado sugar
200g Molasses
MJ Empire Dried Yeast
-------After 4-5 Days-------
2 Star Anise toasted
20g Coriander Seed toasted
3 Cloves toasted
1/2 Cinamon Stick toasted
1/2 Vanilla pod
250g Dried prunes
Muscavdo to prime - Some bottled, most pressure barreled.
I'm looking for medium spicing - there but not overdone.
Any thoughts, Advice?
Cheers