That's definitely plausible but the part of their story that makes no sense is that Collins showed up with a brand new Harley Davidson. The older man "ran back to the house to Google the price of the bike" which came out as £25,000 and it was clearly bought with "his money". That scene is utterly bizarre.
Was it a totally fake scene shoehorned into the memoir to elicit sympathy or generate some kind of visual dramatic moment? Surely Googling the price of motorcycle is hardly a crazy epiphany. How did he know for sure the Collins spent exactly that money on the bike rather than just pocketing it and having spent it on something else?
If Collins bought a bike then that means they didn't spend the 25K on the paddock. Surely Byrn would have interfered by then since he didn't get paid? If they did spend the 25K on the land and simply didn't pay them back, where the did money for the bike come from?? Utterly baffling plot holes
And I'm not a expert in motorcycles but I'm positive the cost of a HD can vary hugely. Just like every single car brand can vary depending on whether you buy it second hand, at what mileage, what model etc. How on earth did that older man find a model that costs exactly 25K, conveniently corresponding with the same amount he lent them to buy land?