You dont screw the slide hammer into the injector like with other types.
The slide hammer uses a special end piece that slides under two machined edges on the injector body.
You can use a small pry bar to carefully lever the injector out but dont lever on the solenoid body just the actual injector.
Once you remove the injector clamp the only thing holding them in is the O ring seal.
I've taken mine out several times with no problems.
The special tools for removing and replacing the O rings and copper washers are a waste of money. You can do it with your fingers and a craft knife blade.
How much would the tool be from LR? It may be worth buying one and getting it copied. That way you have all the measurements you need. If you could sell them for a decent price I'd buy one.
I agree with comments above you can make a simple tool that sits under the flats on the sides of the injector from a couple of bits of 3mm flat steel welded at right angles, you just need to be able to get a good grip to overcome the resistance of the o ring. If I can arrancge it I'll get a pic of one I made, cost nothing.