You learn to drive properly though in a Series, my lad is now 24 never had an accident, now drives a BMW 3.0L Z4 Coupe, insurance less than £900 fully comp.
Go for the Series, I bought my lad one when he passed his test at 17, insurance was £660, Defender insurance is way more. Series are easy to work on and parts are very cheap.
Snorkel yes, door rubbers don't bother, you won't keep the water out of a Series, better to let it fill up and drain afterwards, stops it floating and losing traction.