Hi Roly,
I am at work at lunch, and had a quick look on the TNA website.  You can search to see if naturalisation papers exist on line.  If they do, then you need to employ a researcher to find the paper, and photocopy/scan it for you.  But there were no matches under Rekert, Reikert.  These were the matches under Reichardt........but none of them seem to be your man??
HO 45/9414/56880   Nationality and Naturalisation: Reichardt, Christian, from Oldenburg. Certificate A1960 issued 31 July 1876.    1876   56880
HO 144/103/A20712   Nationality and Naturalisation: Reichardt, Henry Christian, from Germany. Resident in London. Certificate A3797 issued 6 November 1882.    1882   A20712
HO 144/103/A20712B   Nationality and Naturalisation: Reichardt, Frederick Henry, from no foreign state. Resident in London. Certificate A5882 issued 20 August 1888.    1888   A20712B
HO 144/390/B20746   Nationality and Naturalisation: Reichardt, Joseph Paul, from Austria. Resident in Kingston-upon-Hull. Certificate A8903 issued 9 April 1896.    1896   B20746
HO 144/390/B20748   Nationality and Naturalisation: Reichardt, Alexander, from Austria. Resident in Kingston-upon-Hull. Certificate A8924 issued 16 April 1896.    1896   B20748
HO 144/901/175127   Nationality and Naturalisation: Reichardt, Christian Philipp, from Germany. Resident in Highgate. Certificate 17966 issued 12 April 1909    1909   175127
HO 144/17784   Nationality and Naturalisation: Reichardt, Bruno Alexander Ferdinand (known as Boris Ranevsky), from Russia. Resident in London. Certificate AZ3247 issued 25 July 1933.    1933   524463
HO 1/20/241   Naturalisation Papers: Reichardt, John Christian, from Prussia. Certificate 241 issued 20 October 1845.    1845    
HO 1/90/2922   Naturalisation Papers: Reichardt, Alexander, from Austria. Certificate 2922 issued 16 May 1859.    1859   
I will try to post again later, maybe with more information.
Kind Regards
Trippy