Tier 2 & Self-employment

[Wonderberry]

Having read majority of the threads here on self-employment, I see that general view is that self-employment outside COS is somewhat a grey area.

I work under Tier 2 for accounting firm (and that is what my COS says as well). I am wondering if I can leverage Shortage Occupation List (SOL) and start a side-venture (<20 hours) alongside my Tier 2 work of creating my own product which will fall under SOL? For example, I want to design and sell a new pen and this can fall under line "2126 Design and development engineers" of SOL.

Will this logic stand at ILR stage?

Guidance I refer to:

226. You do not need to inform us of any supplementary employment, as long as it is:

• in either a job which is included on the Shortage Occupation List in Appendix K of the Immigration Rules, or a job in the same profession, and at the same professional level, as the work for which your Certificate of Sponsorship was assigned; and
• no more than 20 hours per week; and
• outside of the normal working hours for which your Certificate of Sponsorship was assigned.

In addition, you must continue to work for your sponsor in the job recorded on your Certificate of Sponsorship.

[quoala]

You can have a secondary job with the same job area that you got your Tier 2 visa under condition that you're still satisfying your primary job, as long as it's PAYE, no LTD contract but legit part-time work that the company pays the tax for you just like your primary job.
For Tier 2 visa, you can not take a up any self-employment role.