travelling was not an easy business in this era.

I think it's very easy to forget that travelling swiftly, in relative comfort and safety was the perserve of the rich, and the majority of the population did not travel greast distances with any great ease.

Travelling by one's own coach was really an activity for the comparatively priviledged few ;-)

The roads were generally in a poor state- no metalled roads as we know them- so travelling was not a comfortable experience on badly maintianed roads. It could aso be a long drawn-out expereince with the necessity, if one had one's own coach, of changing horses frequently every few miles with resultant delays.

The coaches were also cold places to be in the winter.etc etc...and ,of course, if the Gardiners only had one carriage, therefore not every child, and accompanying servant(s)- nurse maids etc etc - could be accommodated without much greater expense. The extra expense woulod ahve involved the hiring of another carraige and horses to pull it, plus coachman and post boys to drive the carriage etc.

I say the Gardiners "only have one coach" but setting up a carraige was an expensive business: Edward Copeland in the chapter entiteld "Money" in the Cambridge Companion to Jane Austenremarks on its importance as an indicator of wealth in a family:

Number of servants mark income at the lower levels: the acquisition of a carriage does it for incomes that are a bit higher; and " the house in town" certifies the presence of great incomes , usually those belonging to the prosperous landed gentry...

This higher range of upper professional incomes marks the most prosperous pesudo-gentry families, though Mary Crawford , the rich London heiress in “Mansfield Park” doesn’t think much of its potential :"You would look rather blank Henry" she tells her brother, "if your menus plaisirs were to be limited to seven hundred a year".

It’s most significant consumer marker becomes the ownership of a carriage . Jane Austen’s father took a carriage when his income reached £700, though he found it too expensive to maintain on that income. Mr Perry the local physician in “Emma” lets his income be known to Highbury when Mrs Perry begins to long for a carriage. The ambitious Mrs Elton in “Emma” rubs everyone’s nose in her ownership of a carriage :"I believe we drive faster than anybodys” she boastspages 134-5.

Ther is also another practcal point to consider: where would the Gardiners and their children plus their servants sleep at Longbourn? I'm sure that though it was a decently sized house accommodating all those extra people might have strained even Mrs Bennet's generous houskeeping to the limit.

The Gardiners proably undertook the journey form Gracechurch Street to Hertfordhsrie without their children for any number of reasons, but I think that the practial logistical problems casued by mtransporting their troop of children plus servants to Longbourn for Chirstmas may have played a great part in their decision to leave them safely in London.