I don't shoot weddings in any sort of professional capacity, so have no idea how you end up with a final cost, but I'd definitely suggest making it clear upfront what will and what will not be provided. If people are aware upfront, then they'll be less likely to make demands down the line.
Back when I got married (in the days of film) we got a certain number of prints included in the cost, but never had access to the negs. But this was back in the day when perhaps hiring a photographer for the day was cheaper as they supplemented that daily rate with selling copies of prints to family and friends.
With the switch over to digital, it's a little harder to control what happens with JPEGS. And as such maybe it's more justifiable to have a higher daily rate, because you'll be making £0 from selling copies. If you supply copies to your couple then you can be 100% certain they'll be distributed to everyone they know.
The biggest thing is to absolutely cut down the amount you're editing. as a possible customer, there's no way I'd expect to receive 3,000 shots. Even a few hundred seems over the top to me - but that's because I think we ended up with around 20 prints. As an amateur tog, the idea of fully editing 3,000 shots doesn't fill me with any sort of joy.
There could be a halfway house in that you could supply all the images, but only edit, say, 200. With a view to charging more for editing any particular favourites further down the line. the rest you could supply as downsized JPEGS.
Just bear in mind, people will just do just about anything to avoid paying for stuff. So assume any viewing copies you provide (even unedited) will be downloaded and kept.
Especially when they don't see the true value of them. They see you taking the shots and think that the process starts and ends there.
You need to factor in to your final price:
Time for a recce - scout out the venue, look at possible locations for unusual shots.
Time to shoot - this may or may not include travelling time if it's a long way away.
Time to edit - this is the unseen time that people don't expect to pay for.
The other thing to say is good luck. I've often thought of making the transition to shooting weddings - apart from a) I've never thought I'm good enough and b) I don't particularly like people. It has the potential to be a rewarding job when you're capturing people on the happiest day of their lives. (Hopefully.)
But only if you're the one in charge.