I'm training 5 days a week and I'm 11-hours in myself. I'm training at Bristol Airport and the chuffing weather just this minute cancelled today's lesson. Typical.
Anyway, the place I started was choosing a flight school/club (I went with Bristol because they are a club and located within controlled airspace, so ATC from day one!)
Secondly, get your medical done. Class 1 is more expensive and thorough, but if you are looking at going career, you'll need a class 1. My urine test wasn't perfect and I had to seek a second test from my GP in order to clear, which took a further 3 days. One thing I will add is that you will need an Opthamologist (eye test) to fill out the lengthy CAA form for the medical. So that's another £20 or more (TIP: seek out a free Specsaver's eye test voucher online and then they'll just end up charging you £10 admin fee for having to fill out the form!)
Next, or in the meantime, I'd buy the theory books and start studying. I went with Pooley's but the AFE ones are just as good I hear. There's a lot of material to go through and the sooner you start studying it the better. One thing I will say is that certain things like Nav and Comms will make much more sense once you've got experience in the cockpit, but it's still good to go over. Study Aviation Law and Operational Procedures first, would be my advice. You need to pass Av Law before you can go solo anyhow.
These books will cost in the region of £150 (Flightstore have an offer on for the entire collection of Pooley's books right now)
Equipment wise, you'll need things like, a chart, pens, nav ruler, protractor, notepads, fuel tester, logbook, kneeboard... budget around £200 for the miscellaneous. More if you want a headset.
Most will tell you not to pay upfront and it's sage advice. However, I have paid upfront. But I have my reasons and rationale. If you are to do it, however, at least put it on a credit card so you are protected. If you can get the same deal without paying upfront, do it that way.
Your deal sounds about right, although I'm learning in a PA28 for nearer the same price. What Manc said above me, however, is spot on. Your package is 45 hours, so if you go over that minimum make sure you've budgeted it in. Find out the hourly rate for dual training and cover yourself for an extra 10 hours or so just in case.
It's one of the best things I've ever done and spent a chunk of money on. I'm only just starting, but if you have any questions... fire away. Good luck!