It sounds like your girl has discovered a very effective way of getting your attention and is turning it into a game. Since you mention it only happens when you’re alone with her and not when your DH is around, it seems partly situational: she’s learned “when it’s just us, I can pester mum and it’s playtime.” is your husband more strict with her?
The fact she’s “comparatively gentle” and excited, not fearful or angry, is good. But that doesn’t mean it isn’t painful or frustrating for you. Also, it seems like you've started a routine: since leaving the room is your “only option,” she may not yet connect that with “play ends.” Instead, she just restarts when you return.
Two hours of walking is great, but terriers are clever working dogs. They often need mental stimulation (problem-solving, scent games, structured training) as much as, or more than, physical exercise. If she’s under-stimulated mentally, she’ll make up her own games… and unfortunately, she seems to have chosen this one.
You need to break the reinforcement loop. At the first sign she’s gearing up (barky, bouncy energy), calmly preempt her with a “job”: ask for a sit, give her a chew, or direct her to a toy.
If she bites, avoid dramatic reactions (that’s fun to her). Instead, calmly step behind a baby gate or close a door for 30–60 seconds. The key is consistency — every time bitey-play starts, access to you stops. EVERY TIME and IMMEDIATELY, but only for a short time. Repeat until she gets bored. Yes, you may find yourself doing it for hours at first, but you need to stay consistent.
Also, change the context. Try not to sit around as “easy prey.” Move her into an activity before she gets to that point (enrichment toy, a short sniffy session in the garden, training). If she knows she gets predictable, fun games with you (rather than random wrestling), she’ll begin to wait for those instead.
If you try this consistently for a few weeks and she doesn’t improve, it might be worth a session with a qualified, positive-reinforcement trainer. They’ll be able to observe her body language and the exact interaction, and help you break the habit more quickly.