Questions about Permitted Work and Self Employment

Hi! I've read the guide about Permitted Work when claiming ESA and searched this forum, but haven't quite found the answers to all the questions around my situation - I wondered if I could ask for some help?

I intend to try to claim ESA - I've been ill for a couple of years with various neurological problems, (including a progressive, degenerative spine disease) but have never claimed any help before. Through the development of my illness I have struggled to keep working, though recently this time this has amounted to little more than 5-7hrs a week. I'm now forced to try to get some financial help.

My work is self-employed as an Artist. I have a studio at home which is my only current place of work. I also have a portfolio website from which I also sell paintings, and occasionally supply work to some galleries for sale on a commission basis (i.e. if the work doesn't sell, I receive no payment).

There are two elements to my work:-
a) Making work, keeping in practice, for which I receive no renumeration,
and
b) payment received for paintings which are sold (I don't have any other income from this work, like teaching or suchlike).

I only get paid when a painting sells, and this is very infrequent, however when a piece sells I receive possibly £80-400. As a self-employed person I obviously lodge this in my accounts and submit a return annually to HRMC with an annual turnover figure (at present this figure is small).

The only thing that outwardly shows me to be working is my website with e-commerce facility and my work being available via some limited outlets - obviously I am not supervised by anyone.

Nothing in the nature of this work would contradict any statements I make about my work capacity - the work is entirely adaptable, I don't have to work if I am not able, the nature and duration can be entirely dictated by my condition. Paintings can remain available for sale even if I'm entirely unable to work (as my husband can dispatch any orders I receive through my website), or galleries may be working on my behalf to try and make sales of work I've previously produced. (possibly years ago).

If I was successful in a claim for ESA (I have sufficient contributions to claim Contribution Based ESA and I think I could potentially be eligible for the Support Group, but certainly seem to have more than sufficient points for the WRAG) and did Permitted Work (at the permitted level of up to 16hrs / no more than £115.50 a week for the allowed period)....
a) Could I keep my art business running whilst my application is being considered, or would I be prudent to 'close up shop' and seek specific approval to do this particular Permitted Work if my claim is successful?
b) As I don't earn a hourly rate, would any renumeration for work sold be averaged over a month or financial year (or would a payment coming in of say £200 mean I'd broken the rules of Permitted Work)?
c) As a cautious approach, I presume I could keep up my artistic practice as a hobby (keeping my website), but remove the ability on the website to sell work and not otherwise offer any work for sale anywhere?

Sorry for the long post! And thank you for your help!