I recently received an offer from ACN, but turned them down for a number of reasons.
I'd push to go in at C3 level.
C1 level is approx £38k
C2 level is approx £42k
C3 level is approx £52k
These are all the minimum amounts they will offer for each grade. I was offered a C2 at £46k, but there is no bonus or car allowance, which isn't great...one of the reasons I declined the offer.
The big step up is at Manager level (M1, M2, M3), which starts at £68k, with a bonus and £6k car allowance. They keep the real benefits at that level to increase competition at the lower levels, and to encourage their resources to succeed.
Their overall package is very good; 30 days holiday (exc bank holidays), discounted share prices, double contributory pension, healthcare, 75hrs L&D/yr.
1. see above
2. 2 weeks should be enough