Where I worked we had a lot of staff take redundancy or just leave; many finished on Friday but came back on the following Monday into the same job! The reasons for most leaving was to get more money and the employer was happy as they didn't have to pay so much in 'hidden' costs* of employing those people. Of course when the project they were on completed many where out of a job and onto the job seeking market.
*Hidden costs are NI, management costs, accountancy, failure insurance, Public Liability Insurance, vehicle costs, communication costs (today you cannot use your personal phone's as tax deductibles) just to name the first ones that come to my mind. Your insurance costs will be high because of working at height.
If you are really serious before you anything about applying for redundancy go and speak to an accountant who specialises with small businesses - not a bank manager. With the move to 'Making Tax Digital' accountancy costs are likely higher due to more frequent reporting. In my experience don't use an 'Umbrella' company to handle your affairs; do the work yourself with accountant support, I did use one for a while and it cost me not far short of 40% of my daily rate when I went contracting.