From the earliest days of Guiding, the movement sought to cater for as many girls as possible, to really fulfil the claim that 'Guiding is open to any girl who is able to make the Promise'. The first Guides, after all, were Girl Scout Patrols and independent Girl Scouts who had established themselves independently, then sought an adult to take charge of them when they had had to transfer to being Guides and the rulebook insisted they must have an adult female as a Guider. In urban areas, the gathering of local Patrols into units was a natural result, but in some areas, where girls were more isolated, it was not feasible.
The first problem lay with girls who lived in rural areas. In those days especially, many more people lived in the countryside, in small villages or hamlets, or in isolated farms and rural cottages with few links to the outside world, than is found nowadays. In an era when public transport was limited, cars an impossible luxury, and mass communication even rarer, there were many thousands of individual girls who did not live within feasible reach of a unit (especially given most units met in the evening), and some villages which would always struggle to muster enough girls of the right age or near enough, to ever form the two Patrol minimum needed to start a unit. In many cases, their only transport to the nearest larger village or town, if any existed, was the school bus or train, the timing of which ruled out any participation in after-school activities for those outwith walking or cycling range.
Another group were some of those girls who attended boarding schools. Where a boarding school had a Headmistress sympathetic to the movement and Mistresses willing to take on the role of Guide Officers in their limited free time, units could flourish, and many did - but in schools where there wasn't a Guide Company established, school timetables and bounds rules usually made it impossible for a girl to join any nearby Guide Company, at least during term time.
A further group who were catered for by Lone Guiding were Extension Guides, as they were then known. In the early 20th century, any education for the disabled was often patchy or more often non-existent. The lucky few were sent to special boarding schools catering for specific disabilities, often from a very young age. Otherwise, children who were physically unable to attend the local school were usually stuck at home, often with limited contact with other children and no educational provision or training in practical skills, in some cases rarely leaving the room in which they lived. Letters of activities from the Lone Guider could both give them a connection with the outside world they were isolated from, and also a valuable chance to do some of the activities other girls their age around the country were doing too - a rare chance to be 'the same'.
Technology has brought advances for Lone Guiding, with email and the internet making it much easier for the Guiders to keep in touch with members in remote locations than in the days of handwritten or typed letters sent from hand to hand by post, allowing scope for more regular communications, for challenges to be sent and replies received more quickly, including the creation of an internet Guide unit. And although there are no longer the housebound disabled girls, and far fewer girls living in isolation due to geography, there are a new band of Lones - those who cannot attend units because of their other commitments. With so many out-of-school clubs on offer to girls nowadays, plus the pressure of schoolwork, sometimes it's hard for girls who want to be Guides to find a unit meeting within range on a night which doesn't clash with the other hobbies - so even in urban areas where standard units are available quite nearby, girls are finding that 'Lones' offers them accessible Guiding, which can be fitted into their schedule - so Lone Guiding is currently undergoing a massive expansion, with more units needed to meet demand than for a long time . . .
And in 2020 - the coming of the Covid-19 virus meant that regular unit meetings were cancelled. Overnight, units moved to effectively being Lone units, with those Leaders whose schedules allowed it holding 'meetings' by sending out weekly activity newsletters by email or facebook, or by holding videoconference meetings.