Hi Marie,
Any other bits of information that you may be able to give to us may help us in your research. e.g. Can you estimate what year John or Bridget were born. Baptismal records in Kiltullagh go back to Oct 1839. You may have this from their death records. What district were the children's birth records located in the UK? Can you tie down the year John Burke arrived in the UK. There may be articles in the Roscommon Herald - a local newspaper. There may be a Fenian record in the National Archives for John. Have you checked Find my past criminal or petty sessions records? If we knew what townland John came from we may be able to find his name in the cancelled land valuations records. As regards Margaret Lyons probate records may reveal some information. I have an example of a Margaret Lyons Probate record :
Lyons Margaret (267) 4 July 1939
Administration (with the will) of the personal estate of Margaret Lyons late of Carrick, Ballinlough, Co. Roscommon Widow who died 11 Dec 1933 granted at Dublin to John Lyons, Farmer, effects £7 15s.
Will: I Margaret Lyons of Carrick Ballinlough, Co. Roscommon declare this to be my last will and testamen. I hereby revoke all former testamentary dispositions. After my death I will bequeath and devise all I die possessed of to my son John Lyons and my son Bernard and to my grandaughter Mary to be divided equally between them to the exclusion of all others whatsoever all my property both real and personal I bequeath and devise to John, Bernard and Mary with an equal share to each after payment of all my just debts and testamentary expenses. Dated this 18th day of October 1933. Signed Margaret X (her mark) Lyons. There are a few official documents with the will - mentioning John Lyons of Clooncan, John Lyons of Clooncrim and Thomas Lyons of Cloonbunny, Loughglynn.
Can you give us information on how you knew of Rabbitborough, etc.
I have a contact in Australia that may have already researched the Bernard Grealy/Lyons side that you mention, but I will wait to see if you have any further information before contacting him.
Regards,
Martin.