If you are finiding it hard to get the documents for the employment gaps you can order a 5 year HMRC tax statement. Below is the number to call and this takes about 3-4 minutes to complete. You must ensure that you know your NI number as this will be requested.
It normally takes about 10 days for the HMRC to send the 5 year tax statement. Once received you will have to email it to email@example.com also ensuring that you put your full name down in the subject line.
HMRC Tel: 0300 200 3300 (Low cost number)