AVP is the next tier above Analyst. Barclays have main groupings for grades, then two informal sub-groups within each:
Analyst/Graduate (0 - 3 years experience)
First year analyst
Second year analyst (can be skipped if you're good)
AVP (2 - 5 years experience)
VP (4 - 50 years)
Often the tier people stop at. You need to be leading a small team or business area I believe (e.g. Digital lead for a product) to be a VP.
In salary terms, it varies depending on the area of the business you're in. For Corporate I believe Analyst starts about 33k and goes up to about 38k. I know AVPs who are on 40k and I know one on 56k. Bonuses of circa 10%.
If you're joining the investment bank, your salary and bonus package will be higher. I know an AVP in back office on 60k although believe the upper limit for this is significantly higher. His bonus I believe was 20%.
It would be good to understand if your offer is aligned with the above, if you aren't opposed to sharing.
Hope this helps - congratulations on your offer.