> First, at what point would you start looking at leading indoors? I'm currently climbing successfully about half of the 6a+ I try after a few attempts and normally get to the top of a 6a first time although it's a challenge and depends on the route characteristics.
When to lean to lead, depends on what grades the lead routes at you wall start at (provided they've got some routes at grade 5 or below, you're good to go now). I'd recommend learning to lead indoors as there's less to distract you.
Who are you climbing with? Another newbie or a more experienced partner? If another newbie, lead courses are usually £50-70 between two and go through all the essentials.
> Second, I'd love to get outdoors on some trad routes but would I be better served staying indoors and working on technique for a while longer?
Provided you've got a competent leader to take you up the easy stuff, there are loads of classic and really enjoyable Diffs and VDiffs, which you'd be fine on now. Based on your indoor grades, you should be able to progress quickly through the grades on second.