Do you have any advice for potential travellers?
Clothing: We were extremely lucky with the weather, but I would definitely recommend lots of layers, and a scarf/buff/balaclava to protect your face is essential. I took both walking boots and snow boots but didn't wear the snow boots at all. They provide you with chains for your boots (which we found to be essential) and you need walking boots really to use them. You also need walking boots to fit the crampons for the glacier hike. I used a Peruvian-style hat with ear flaps for most of the trip, but you also need a beanie-style hat (no bobble) for the two occasions where you need to wear a helmet. Waterproof trousers and coat are essential as you may get wet in the cave and from waterfall spray, even if it’s not raining (a lens cleaning cloth for your camera is also useful as you’ll end up with lots of droplets on it near the waterfalls). I’d also highly recommend two pairs of gloves – the thin inner pair will protect your hands when taking photos.
Other equipment: I took a flask but didn't use it. There was a kettle in the room at Hotel Laki, but not in Reykjavik. You can easily fill up a bottle with drinking water throughout the trip. It may sound strange, but sun cream may be useful, especially if you go later in the season; it had clouded over a bit by the time we did the glacier walk, but otherwise there would have been a fair bit of exposure and reflection from the sun.
Northern Lights: We were extremely lucky and saw a great display on the last night. However, be prepared to be flexible and keep extra layers on the bus with you just in case. We headed straight from the day's activities for dinner with the intention of then checking in to the hotel and getting extra layers on etc before heading out into the countryside (away from light pollution) as the forecast was looking good. However, the lights had other ideas and appeared for an hour at 8.30 pm, just as we were finishing dinner. We all piled into the bus and headed 10 minutes to a peninsula near the harbour in Reykjavik. So whilst we didn't get to see them against dark skies, we did avoid a long drive and hours of standing outside in the cold, and were back at the hotel by 10 in time to head out to a bar. A friend who went on the trip in January had a 2 hour drive each way to find them on the last night and got back to the hotel at 3 am! When you are at Hotel Laki, if you hear people moving about in the middle of the night and doors going, don’t lie in bed wondering why people were being noisy like I did; it probably means somebody has spotted the lights, so throw your warm clothes on and get up to the viewing area on the roof! I only have a compact camera (Panasonic Lumix TZ30) but managed to get some reasonable photos after doing a bit of research online before I went. I used the manual mode with F3.3, ISO 800, a 15 second exposure, and self timer to avoid camera shake. The key was having a mini tripod with me (that allows you to angle the camera upwards) – even though it’s small enough to fit in my pocket and I looked a bit silly next to everybody with their proper gear, it worked perfectly.