Take a look at the attachment
The two leg "puller" fits into the cutouts of the bush flange, and with the smaller diameter mandrel pulls the bush out of the arm.
The refitting device is a strongback with a threaded bar combined with a mandrel which sits on the rim of the trailing arm.
So in absence of the correct tooling, you can cut out the rubber section, it doesn't have to be the full amount, enough to accommodate a hacksaw blade.
Then cut carefully the aluminium housing of the metalastic bush, this relieves the hold the bush has on the trailing arm, and will allow it to be drifted out.
Clean up the ring in the trailing arm, and a thin smear of grease on the surfaces, and the new bush can be then pulled in using a proprietary device fashioned from threaded bar, and something suitable to use as a strongback, I have various offcuts of steel plate which I use for such things..........it's a question of using your imagination
Have fun, the last time I did this job was about two years ago, and it took me around an hour per side, the hardest job ironically was undoing the bolts securing the toe adjustment brackets
Brian