There is actually a little bit more to the text related to the children of the brothers and sisters. I realised after posting my message that it might be relevant:
"shall be equally divided between all my brothers and sisters that shall be living at my said sons death or at my decease (in case I should survive him) and the child or children of such of my brothers or sisters as are now dead (or shall be so at either of the aforesaid (???)) to be entitled to the part or share of his, her or their respective farther or mother in case they had been living to be equally divided amongst them if more than one, and if but one such child then the share of such deceased farther or mother wholly to that one."
The Will leaves everything to his son unless his son dies before him, in which case the above would have been actioned, but since the son was still alive then I guess there may not have been much in the way of correspondence. I know notices similar to the following appeared at least twice in the Norfolk Chronicle in 1783:
"All Persons having any legal Claim or Demand on the Estate and Effects late John EWING's, of Cringleford, in the County of Norfolk, deceased, are hereby desired to apply to Mr John EWING, of Cringleford, or to William HUGHES, of Hethersett, Executors to the said Mr John EWING, in order to receive Satisfaction of the same; and all Persons that stand any ways indebted to the Estate and Effects of the above mentioned deceased, are hereby likewise desired to discharge the same to the said Executors, in order to prevent any farther Trouble."
...so it is indeed possible that there may have been some correspondence as a result.