I was born in Lindsey, but I have a Dutch Surname.
The divisions go back to Saxon times (or possibly earlier). Some counties were sub-divided for purposes of law enforcement (Assizes), and Lincolne Scire consisted of three parts, one of which was the parts of Hol Land (Hollow or low land). As with other counties, a further sub-division is into Deaneries (e.g. Candleshoe) and further into Wapentakes, of which Kirton and Skirbeck are surviving names. Finally the basic divisions are Parishes.
Why black and amber? Happy coincidence, but I believe that the club took its colours from the coat of arms of the borough (three amber royal crowns on a black shield). These have been the colours of Boston Grammar School since the days of Mary Tudor. The only other borough permitted royal crowns is Kingston-upon-Hull.
I am sure that this is the case. If it's not, then I'll be a Dutchman!