Have one rear trailing arm flopping about at the front where it meets the chassis, assume it means the other is not far off as both were changed at same time by last owner. 

I’d like to avoid buying the tool for one use, and put the money towards better bushes. 

Any experience of removing old bushes in situ without the specific tool? With a cut through the outer ring of the bush (not the arm!) using a hacksaw, I’m imagining it’ll not be too hard to bend and remove. Reasonable assumption or disillusioned?

Looking at using Powerflex (OFR19-1917) replacements, then it’s just done for the last time. They seem straightforward enough to fit without tools, bit of warmth, silicone lube and elbow grease required. 

Any tips on fitting them? 

Cheers, Jamie

Alan shows how it's done (OEM parts):

 

Thanks. Alan makes a very watchable and informative video!

Doesnae look like a job for doing on the driveway in a Cumbrian winter!

We have had an advisory on both sides for about 7 years and they are still OK?
Yours sounds like it has gone way beyond that.
If you DO decide to DIY (Brrrrr!) the tool is "only" £66 (how much will garage charge for the total job?)  - if only it was Summer!