Hi Thommo, I think we talked about this last year after we both DNFd in the swim, and I'm so sorry it happened to you again. If you look at the times, this year's swim was almost as bad as last year, and by the end for us slower peeps, the swell was huge - we just didn't have the massive breakers added in this time.
I know how it feels to be driven on by a DNF, and tried to do whatever I could to prepare this year, though the sea was far too calm whenever I got there! I realised I would never train on my own in rough conditions, so entered the LCW swim and a couple of the salty sea dog Long swims near Bournemouth. Despite always having calm conditions, they did help my confidence and allowed me to practice relaxing into the swell etc. Cost me a fortune and lots of travel time, though. I did also get some technique coaching but frankly don't feel it's worth it when a rough sea in a wetsuit is a world apart from a laned pool (though I did more of that too). Also masses of self-talk into blocking the negative thoughts that seemed central to last year's trouble.
You may be right leaving it for a year, but whenever you do go for it, over-prepare mentally and physically, and you'll be thrilled you did!
When metalwork is removed, the screw holes leave the bone relatively weak and vulnerable to fracture for some months afterwards. In addition, all removal of metalwork risks complications, ranging from minor ones like making the scar worse or tender, through infection etc, and up to major disasters like clobbering the major vessels or nerve plexus that are just behind the clavicle. They are unlikely to occur, but you need to think how you and your nearest & dearest would feel if they did. I always advise leaving metalwork in unless there is a very good reason for taking it out