Wow, thanks for the information and advice guys. I actually thought no-one had replied yet but it turned out I'd forgotten to subscribe to the thread, as the forum defaults to no notification on threads I start/post in (in common with most other forums I've joined but I still get caught out!). So it was a very pleasant surprise to see so many replies when I checked, what a great community you have here
So it seems the Ego-C isn't really recommended. I wasn't sure if it was more or less the same as the Ego, which I had seen a lot of recommends for, but I presume it's not if it has wicking problems, as I doubt the Ego would have ever been so popular if it had those.
Thanks for the advice to get an EVOD kit and to use re-fillable clearomizers (which will last for many months, with only the inexpensive heads needing replacing in the meantime) rather than the atomizer cartridges (which will only last 2-3 weeks) as supplied with the Ego-C kit I linked to.
I might be able to scrape by with one battery as I'm at home a lot, so perhaps if desperate could use it whilst it's plugged into the charger (depends on whether it can work like that, using the input power if the battery is flat, or if the battery has to charge before it will work) and can obviously charge it overnight when I'm asleep but it does seem more sensible to have at least two batteries.
So I'll probably get the EVOD kit that Chrissie kindly linked to for myself and make sure I understand how to use it and that it'll be suitable for my sister before getting her one. As the kit has two clearomizers and five heads, I could split those to start a kit for my sister, then only needing to get her two batteries and a charger and then we can each purchase more heads as needed, which will give us both a chance to try it, without having to buy two full kits. It's not clear if the kit includes the drip tips but maybe they're built-in to the clearomizers? Also, does anything show the battery level, as I think that would be quite useful, for my sister at least? I'm slightly concerned that maybe the 650mah battteries in that kit will be inadequate, particularly as mkbilbo has said his brand new 1100mah ones only last him 6 hours (and it does make me question the honesty of Uniqbuy if they're lying about how long their batteries will run for!)
The EVOD kit company sells the clearomizers for £3.49
Evod Clearomizer SS - Clearomizers the heads for £1.75
Evod Coil Head 2.2 ohm - Accessories and 1000mah batteries for £9.99
Kanger Evod Battery 1000 mah SS - Batteries & Chargers
I think this £3.49 Ego charger is compatible (it says Ego charger in the starter kit description anyway)
Fast Ego USB Charger - Batteries & Chargers so for two batteries, 1 charger, 2 clearomizers and 5 heads that would cost £39.20, which is £10 more than the starter kit and doesn't include a nice gift box (which doesn't matter as it will probably get discarded once the e-cigs are in use anyway) so it's just a question of whether it's worth it, or if I could get a kit with 1000mah batteries for less elsewhere. It just seems a bit daft to buy the kit and then find I need to spend another £19 getting two 1000mah batteries if the 650mah ones are inadequate.