I think this is the one i have : http://www.ebay.co.uk/itm/190631297256?redirect=mobile
Although i had mine given to me so you may be able to get it cheaper?
I'd fit the split charger as well mate, especially for the amount it costs (the one i posted above spruce recommended and ive not had to charge my battery since i it fitted)
Edit : your shuflo pumps are spot on
I haven't one of these chargers but they have a good reputation as a quality charger.
They are only trickle chargers so you they will take a while to recharge a battery. If you have 2 pumps running for a total of 8 hours drawing 4 amps, then you can expect that charger to take all night to fully recharge your battery. If you didn't recharge it that night and used the same current the following day, then your charger wouldn't recharge the battery fully that night.
(A 5 amp charger will take just over 6 hours to return 32 amps to the battery. However, the fuller the battery is, the lower the rate of charge it will accept, hence the reason why it would take so long.)
We have run this for 4 years now. It is bigger than the C-Tec charger. The only thing I've had to do it put a drop of 3 in 1 oil on the cooling fan bearings as they became noisy.
http://www.ebay.co.uk/itm/Numax-12V-10A-Leisure-Battery-Charger-Caravan-Campervan-Motorhome-Marine-Boat-/321156058628?pt=UK_Campervan_Caravan_Accessories&hash=item4ac6648e04#ht_1283wt_994Numax recommend that the charger doesn't charge your leisure battery at anymore than 10% of the battery's capacity - ie 10amps is fine for a 110 amph battery. We haven't had an issue using this charger on the 85 amph batteries.
I plug the battery charger in when I get home and leave it overnight. I'm fortunate to have a driveway and the van is parked on that each night.