~What sort of approach works best? Who do you think should start the conversation off?you or your DD?
Either can, but if my child starts off the conversation, I try to make sure I don't take over and launch into overdrive. It needs to suit each child and parent. I have found that I need 'props' to broach the subject, as my mum didn't ever discuss periods with me. So if one of my dds asked about my tampons or towels/panty liners when they were little, I'd tell them what they are for, in an age appropriate way, little by little.
Then, when they were about 9 or 10 I buy them their own bag of items ready for when their periods start. Both my periods, and DD1's started just before our 13th birthday, so from age 11/12, I'd lend them a small bag of things to take away on school trips and sleepovers, in case they started when away from home, and also a small carry case for their school bag.
When their periods do start, and they tell me, I go into a bit of a social history lesson with added biology! To start with I recommended DD1 used just towels, I explained what the hymen is and how it thickens with age, and is a bit sore when it is first broken (I was surprised this hadn't been talked about in sex ed at school). I explained the cultural differences about the use of tampons for some girls. I told her when I started using tampons, etc and said it was her choice whether (and when) to use tampons. I've bought both applicator and non-applicator type tampons for my girls to try.
~ How does your DD feel about discussing periods with you?
DD1 is fine about it. It's a bit awkward, but she's brought the subject up when she's needed to. She hadn't wanted to use tampons at first and has only recently started to use them (I am amazed I even know this much!) I've been looking around for packs of varied sizes of tampons, so will try to get hold of the Teen Starter Pack for her, it seems ideal.
~ What do you think is of interest or concern to your daughter at this time?
One thing is the fear of it showing through her clothes. I've bought her black knickers, black jeans and always get the ultra towels with wings as well.
Another is period pain, which she seems to find eases with exercise, so she likes to keep sporty.
A third concern is mood swings/PMT. This has improved remarkably since dd1 got a boyfriend. It's amazing how hard she will try to be nice for his sake! 
DD2's period's haven't started yet, but she doesn't seem to be concerned or worried.
~ What about protection? How do you and your DD decide which option to go for - does this change as they get more used to having their period or get older?
Yes, as above. I bought a range of brands of different sizes for her to try out. I explain how they need to use the right size of protection to suit the flow/day for comfort and to be both economical and prevent leaks.
~ If your DD suffers with menstrual cramps how do you manage this?
Initially, in the first year or so, I'd suggest she needed to get a bit more exercise, as I find I don't get as much period pain when I've been active. She can get herself some pain relief from the medicine basket, and she tells me what she's had and whether it's had an affect. I think we've both realised that ibuprofen is good. In the evenings, ask her if I can get her a hot water bottle, might let her have a few squares of chocolate, or make her a hot chocolate or hot squash drink.
Are there any practical things you can do to help your DD if you suspect she is about to start having her periods?
I just let my DDs know that I have a bag of things saved ready for when they need them. They can ask me any questions they like, and I answer as well as I can. I tell them it can be painful (I explain about the dosage for the pain relief) and can affect their moods (but no excuse for nastiness) and to let me know if their periods do start.
~ Finally, mood swings are commonplace during puberty do you have any tips or concerns you can share? - (or should we not even go there?!)
As above, generally having friends (especially boyfriends) around to impress can make a huge difference. Also, to not make too big a deal of it, ask how they're feeling, if they are in pain, offer some pain relief or whatever will help them deal with their own needs, and try to move on. If there's a melt down every single month without fail though, I say that they need to get it under control or they are likely to lose friends, jobs and more if they can't.
~ What tips or advice would you share with other parents about puberty and periods?
Children can get all the information they want to on the internet, or from school. The advances in design and technology of sanitary products in the last 30 years is astounding, and this all makes starting periods a lot less stressful than it was in my day. However, it doesn't make it any easier for mothers to talk to their daughters, and it's easy to let yourself feel that you can buy them a magazine, or just let them look it up on the internet, give them pocket money and let them sort themselves out. If they don't get a hug from their Mum, and their own Mum telling them what it was like for them, and how things have changed, sharing some funny stories and embarrassments, well then you are missing out on one of the best things about being a mum. My mum missed out on all of that, and I don't regret finding my own way of sharing some girly chats with my daughters, we have shared a lot of laughs as well as the pain.
Let the people at Lil-Lets know what you think of their teen starter pack.
really great. I've got the drawstring bags of towels (daytime and night-time) ready for when DD2 starts her periods and will look out for the teen starter pack as well.