Hi MatthewNFW
You will have to set up a liability account, this is to account for the company owes you an amount as you purchased an item on it's behalf, accounting > chart of accounts > New > in the account type select current liabilities > in the detail type select current liabilities > name the account, i.e.Matthews Loan > save and close.
Then create a Journal Entry to account for the item that you purchased personally and increase the amount in the liability account created above, select the create icon in the top right hand corner of the screen > under other select Journal Entry > in the account column select an expense account that is relevant and in the debit column enter the amount > In line two in the account column select the liability account you created above and in the credit account enter the same amount as entered in the debit column > save and close.
When the company returns the money to you/you debit it from your account you will have to create an expense, this will reduce the amount populated in the liability account. Select the create icon in the top right hand corner of the screen > under suppliers select expense > you can enter your name as a supplier in the payee box however it is not necessary > select the bank account the company paid you back from in the payment account > enter the date the money was debited from the account > in the category section select the liability account you created earlier > in the amounts are box select No VAT enter the amount in the amount column > save and close