I think you need to differentiate there between 'commercial forestry purposes' and 'other commercial purposes using a supposed forestry shed'. Planners will not be at all sympathetic on anything which tries to use permitted agricultural / forestry planning regs to get a building that morphs into being used for other purposes, even if it involves the timber or wood as part of a later process. We've had a couple of posts including the original query where people still don't seem to have twigged that.
a place that we can craft artisan woodland products on site
The agricultural planning is meant to facilitate managing the wood, not having non-forestry activities in a shed there. Turning the wood into end product is manufacturing, not forestry. You can store kit there that you need to fell, cut and shift the trees, but not be entitled to build a picture framing business, walking stick factory, wood-fuelled pizza restaurant, wooden boat yard, oak flooring or fence panel business. Those can all be done away from the wood, while it might be convenient and cost effective to you, its not essential to have the building in the wood to carry out those activities. Commercial buildings for non forestry uses might actually be permitted, but you'll be hit with rates and it'll need an application for a workshop, factory, retail area or whatever you want to call it and it will be seen as a change in use of the area from agriculture to another purpose.
I'm not saying I agree with that rigid interpretation, that's just what you're going to get from the planners. Farm shops for example, are usually permitted on farms, but won't be built or come under agricultural planning, it'll be a retail building and it'll have its own hoops to jump through such as hygiene, disabled access, fire escapes, traffic impact, etc. If done in a former barn it'll come as change of use from agricultural barn to commercial retail premises.
I'm hoping the storage of timber under cover while it seasons is seen as part of 'forestry' in the same way as storing grain or milk on a farm until it's collected is an inert part of the agricultural process rather than hands on commercial activity. Curious that letting the weather dry something is in reality adding value, even though no human activity is involved
I think this is a grey area and await clarification from the planners that timber storage is deemed OK as storage of a 'raw' agricultural product. I'm a bit stuffed or will have to work round it if its not.
This legislation may restrict us but it also protects us from adjacent wood owners suddenly turning their wood into a theme park, dump, car breakers or fracking site.