My and my ex partner are trying to do a transfer equity.
He wants the house, and as I have already moved out I am happy to sign my half of the house over to him.
Before he fills out the form though, he wants me to sign it. He saying that unless I sign the blank document first he's not going to fill it out at all.

My question is, if I did sign it first, is there anything he could to screw me over.
I haven't got a clue what sort of information is on there as he won't let me look at it, so I'm not sure if there is anything he could do that wouldn't benefit me!?

Hurrah! Never sign a document that doesn't fully disclose the terms of the contract. I need a bit more information, though I would have to see a map to locate Wales. Is the property held as collateral for any debt? Also, doesn't the form require witnesses?

No, no debt. I'm not sure if the form requires witnesses as he hasn't let me look at it!
I've been trying to get in touch with my mortgage company, but I can't seem to get through to them.

We are mis-communicating. Why are you contacting your mortgage company if there is no debt?