Raisin skins can harbour wild yeasts and bugs, so I'd give them a toss in a hot wok to sterilise them maybe.
It was a fine beer that one, you're brave only doing 10l.... last time you said you'd wished you'd done a bigger batch... 😉
Haha I did but I also ended up with lots of overcarbed bottles after a few months so sticking with a smaller batch so Im not dealing with a shit load of bottle bombs come spring time! Hot wok I've seen suggested by that denny chap who seems to know a bit so will probably do that and the rum soak to be sure. The toasting helps to bring out the flavour too apparently so double bubble