Starting Out Self-Employed

Neddy139

Hello! 

Long story short...started a new job in Feb 2020, furloughed late March 2020, 3 month probation extended due to COVID-19, been told that my job is potentially at risk as was a new role within an expanding company and obviously business has shrunk rather than grown and business still pretty limited. Due to catch up with manager in coming week.
Have been doing some self-employed work (with their consent) for last month or so and things are going reasonably well. Will be carrying it on if I lose my job.
My existing laptop is about 8+yrs old so thinking of investing in a new MacBook (about £1000) - using ‘cash accounting’ can I put the whole cost down as a business expense on date of purchase? 

My idea would be to put 100% of cost as only use laptop for working, if I do keep my job and then the self-employed work diminishes, I could always go back and change it for a smaller % as the expense? 

Does this sound reasonable & correct? 

Any advice or other ways of doing it would also be great! Thanks very much 😊