With EnduranceLife I'd go for the Flete marathon - it's later in the year and only category 3 (strenuous) in their category system. The South Devon one in early February might not be a good idea for a first one and is graded 4 (severe), whilst the North Devon one (Exmoor) is '5' (extreme).
In Flete there is quite a bit of pleasant running through woods and a very interesting 600m estuary crossing. Be sure to consult the tide table to find out how deep it will be! I think though that the organisers plan the date of the event based on there being low tide at this point.
The good thing about their events is how well waymarked they are. They even have signs with crosses on on the paths you are not supposed to use. Hard to go wrong.
Just to be clear, I said 'beginner friendly' as there is a good range of ability and picturesque location; so you can say you were just there for the view
Not sure of the particular Ale served but my last Marathon featured a pint at the halfway point from The Grampus Inn! followed by a mile long climb with an average gradient 1:10!
But there is a Sportive sponsored by the Exmoor Beast brewery called, oh what was it..... Ah! The Exmoor Beast! Its on the 19th of October same day as the Exmoor Stagger the Stagger wins for me, great race!