I use the previous version of this (which was called the Ctek 3600): -

http://www.ctekchargers.co.uk/ctek-mxs-3.6.php

Bought on eBay, via a small shop, quick delivery and it has never let me down and won't overcharge the battery on the Aero.

Here is one on eBay from a seller with 100% on circa 5,000 transactions: -

Ctek MXS 3.6 (replaced the old Ctek 3600)