Thanks all for the replies.
My thoughts on a couple of points that have been well made;
- theft or damage. Is this a significantly higher risk in the arb industry? outside of the arb industry I know it is a problem, but I suppose it must be manageable. The fact that there are profitable hire companies shows that.
I know arb work is hard work for both people and machines, so I would expect and accept a certain amount of wear and tear and cosmetic damage, but there must be insurance and security measures available to mitigate the risks well enough
- maintenance and repairs. As above with theft damage; it must be manageable? I am reasonably mechanically minded and can learn fairly quickly. My first job out of school was a tractor mechanic / fitter, and I have been a been a farmhand, bicycle mechanic, I do a lot of my own car maintenance and my current day job is an engineer in the automotive industry, so I have a reasonably good understanding of mechanical and hydraulic systems, so I'd be reasonably confident to do basic repairs and maintenance stuff myself, and I guess I would rely on either the supplying dealer or approved repairers for difficult stuff. Any machine I bought would be a known and well supported make, I would avoid any of the chinese stuff that is admittedly temptingly cheap.
- breaking into a saturated market, competing with existing companies. Alongside a lack of demand, this is my biggest worry. Thank you NJA for identifying a couple of companies nearby who do similar. I had a look at their websites and it looks like they have a variety of excavators and various arb attachments, but neither offered a tracked mini skid steer. So while it's a bit niche, it might be something that would be in demand? Certainly when I was working as a groundsman our mini skid was much more versatile and useful for most things than the mini excavators that we also had on a couple of jobs.
I am hoping that building a good relationship is where I would be able to do OK. I would be a sole trader operation with quite a narrow focus, so I would hope that my overheads would be lower and that I could be cheaper and offer decent flexibility than the bigger players.
I am also very fortunate in that I have a wife who earns enough, as well as having my office job to fall back on if it all goes pete tong, so I could afford to start small and build slowly. I wouldn't need it to immediately pay off; to begin with I would set merely being cost neutral as a target, then if/when I achieve that I could aim for profitability (or if it's a total failure I could pack it in and know that at least I tried).
As I touched on in my opening post my current job is making me pretty unhappy in general and despite being an engineer, I very very rarely get to do anything other than sit and stare at a monitor. I like working outdoors and doing something real, so if I could make some money by trundling around the countryside with a machine in tow, or occasionally doing basic work on the tools again, that would be great.