Welcome back. My experience with D1's has been second hand through my two boys who bought GEMS 4.0 D1's when they got their driver's licenses. Each got 3-5 years of good use out of them before they needed head gasket jobs. Both have mileage in the 180-190K range and keeping them on the road was doable on a high school/college student's budget. Prices have jumped I'd say over the past 12-18 months, but what hasn't? They've learned early that vehicles require care and maintenance and to save your cash for a rainy day. As a Defender owner yourself, you'll be fine with a $9K budget, it'll be how you spend it. All in on a nice one that's got proof of service or over time as you work through the typical list of hoses, sensors, brake lines, radiators, fuel pumps, tensioners, alternators, water pumps, belts, expansions tanks, etc.
I'm in NOVA and my youngest son has moved on to a more fuel efficient vehicle bc his job requires a lot of driving. PM me if you're interested in discussing what he's selling.