Understanding a UK Self Assessment

I’ve recently accepted a position teaching dance classes outside of my regular employment.  I expect to earn c £2,000 annually from this role.

I currently pay tax through PAYE in the highest bracket.  Needless to say, I’d love to maximise any allowable deductions on my soon to be required self assessment to reduce tax exposure.

Am I correct in thinking these items would be allowable deductions?:
(Dance) shoes
(Dance) clothing
Sound system

More of a grey area:
Mobile phone
Vehicle expenses (if this is allowed, how far can I push it?  Just mileage?)

I would love any guidance you guys can provide.

I’ve recently accepted a position teaching dance classes outside of my regular employment.  I expect to earn c £2,000 annually from this role.

I currently pay tax through PAYE in the highest bracket.  Needless to say, I’d love to maximise any allowable deductions on my soon to be required self assessment to reduce tax exposure.

Am I correct in thinking these items would be allowable deductions?:
(Dance) shoes
(Dance) clothing
Sound system

More of a grey area:
Mobile phone
Vehicle expenses (if this is allowed, how far can I push it?  Just mileage?)

I would love any guidance you guys can provide.

My situation was substantially different so I'm not sure how relevant this is but when I briefly looked into UK deductions, I found that they were far less generous than in the US.
I clarified with HMRC directly but  basically, I couldn't deduct anything that I thought I might be able to! 

I found a very well written article directed at show business and what is and isn't allowed.

Seems:
Dance shoes/clothing CAN be deducted as they are not dual use (I won't be shopping at Tesco in tap shoes)
Sound system (capital expense that can be amortized over the expected life of the sound system)
Mobile phone (only calls directly associated with the business, so NOPE)
Vehicle expenses (mileage only)

I'll take that!  Should be about £400 of deductions which is nice. 

I found a very well written article directed at show business and what is and isn't allowed.

Seems:
Dance shoes/clothing CAN be deducted as they are not dual use (I won't be shopping at Tesco in tap shoes)
Sound system (capital expense that can be amortized over the expected life of the sound system)
Mobile phone (only calls directly associated with the business, so NOPE)
Vehicle expenses (mileage only)

I'll take that!  Should be about £400 of deductions which is nice. 

Excellent, that all sounds very reasonable. It looks like the mileage rate is 45p/mile

https://www.gov.uk/government/publications/rates-and-allowances-travel-mileage-and-fuel-allowances/travel-mileage-and-fuel-rates-and-allowances

I am not sure that I would claim for dance shoes. If I did, I would want documents to prove the shoes were never used for anything but dance and they were required by the job.
Nix on the clothing, of course.
Sound system, not a problem as long as it's not transportable. If it is, see above.
There are all the costs incurred on this trade before you started trading, which you can bring forward.
Advertising, printing.
Working from home (room utility costs for session mixes)
Land line phone, apportioned.
Arguably, use of computer (accounts, marketing, social media) cost apportioned.
Maybe if you took students at home you might be able to establish home as a place of work and therefore claim costs of travel from place of work A to place of work B
If you create losses you can offset them against PAYE income.
Don't forget the 1k trading allowance

I am not sure that I would claim for dance shoes. If I did, I would want documents to prove the shoes were never used for anything but dance and they were required by the job.
Nix on the clothing, of course.
Sound system, not a problem as long as it's not transportable. If it is, see above.
There are all the costs incurred on this trade before you started trading, which you can bring forward.
Advertising, printing.
Working from home (room utility costs for session mixes)
Land line phone, apportioned.
Arguably, use of computer (accounts, marketing, social media) cost apportioned.
Maybe if you took students at home you might be able to establish home as a place of work and therefore claim costs of travel from place of work A to place of work B
If you create losses you can offset them against PAYE income.
Don't forget the 1k trading allowance

It's pretty hard to use tap shoes for anything other than tap dancing.   

Will I get the trading allowance even though I have PAYE income?  I was under the impression that I would NOT get that.  If I get that, then that's fantastic if my first £1k is not taxed at 45%.