@Mummaunicorn Appreciate I am a week late but I couldn't just read and run because whilst the advice you've been given is generally good it is also a bit idealised. What should happen is that you should be protected from your abusive ex. What will happen is much more dependent on human frailties including those of people in authority and therefore it is not enough for you to get support from Women's Aid; what you need is hard evidence against your ex to convince a court that you need a Non-Molestation Order and - potentially - that he should get a custodial sentence depending on his offences.
First, an explanation. Think of the cover all term as a series of concentric circles. The outer ring is what organisations like Women's Aid and Refuge consider to be domestic abuse. This can be serious criminal conduct but it can also be ideological. These organisations believe domestic abuse is a gendered issue whereas the courts do not. Consequently, they will provide refuge and counselling for forms of domestic abuse that neither the Family Court nor the Magistrate's Court will necessarily view as abuse (e.g. interrupting you when you are on a phone call, following you around the house unless you can prove you were intimidated by it). The reason I mention this is that these are not going to be the most compelling examples to gather evidence for.
The next circle is what the Family Court will accept as a good enough reason to issue an NMO. There might not be enough evidence for a criminal conviction but his threats to commit suicide or threats to make false allegations against your family (provided you have at least some of these in a written form as a text message) should be enough evidence to put in place an NMO. If he breaches the NMO, he will get a custodial sentence so he has a very good reason to stay away from you. However, unfortunately because of people just like your ex you will need hard evidence. The problem is that the Family Court has to deal with false allegations on a regular basis (false allegations are a form of abuse, which I suspect you are already well aware of) made by people seeking an advantage in custody cases, financial settlements or simply to carry on controlling their victim. You said you had photographs and videos though, so I suspect you should be able to get an NMO and the authorities will move quickly to protect you. Change the locks the same day you apply for one.
The last circle is what constitutes a criminal offence. This is a narrower set of offences than the Family Court will consider and will include battery, coercive control, economic abuse and making false allegations for example. It sounds like he's guilty of some serious offences and you need to try and document them all and make sure you get your facts right. The risk if you get a date wrong for example is that he could provide an alibi for that date and dent your credibility. So do get your facts absolutely right. Women's Aid should be able to help in that respect.
Finally, some general guidance. Change your locks. Ignore his suicide claims, he's lying. Change your phone number. Change all your passwords (ALL of them). Close any accounts you share with him. Make sure your family are aware you are at risk and make arrangements with them so they know you are safe.
Oh, and I'm sure your business will be fine from the false allegations of this toerag and if he wastes police time, they'll waste his. About 6 months worth in fact.