Hi Kerryb
I just looked up some of the entries you refer to (to give me a better idea of the whole family) and will post here because now I have typed them out they might be useful to others:
1871 Warbleton
John SMITH head mar 39 ag lab b.Lamberhurst Kent
Emily wife 38 b.Horsham
Emily dau 18 b.Ore
George son 14 b.Rye
Mary Ann dau 11 b.Ashburnham
Bertha dau 8 b.Battle
William son 6 b.Warbleton
Lorraine dau 4 b.Mountfield
Florence dau 1 b.Warbleton
RG10/1045 folio 30 page 24
.............
1881
Netherfield Place Farm Barn, Battle
John SMITH head mar 49 b.Lamberhurst Kent
Emily wife 48 b.Holborn Middlesex
Bertha dau 18 b.Battle
William son 15 b.Warbleton
Laura dau 14 b.Mountfield
Flora dau 11 b.Warbleton
Jessie 8 b.Wartling
Thomas 4 b.Mayfield
RG11/1034 folio 34 page 21
..................................
1891
Darwell Hole, Brightling
John SMITH head mar 59 gen lab b.Lamberhurst Kent
Emily wife 58 b.Horsham
William son 25 gen lab b.Warbleton
Thomas son 14 gen lab b.Mayfield
RG12/768 folio 117 page 19
.............................
1891
3 Dragon Houses, Wartling
Edwin HAFFENDEN head mar etc..........
Emily wife 38 b.Hastings
Rg12/776 folio 130 page 10
Emily must be Lorraine's sister b.Ore (Hastings)
Emily LOVEKIN m Edwin HAFFENDEN 1877 Eastbourne RD.
I think there's little doubt that you have the right family here ......... there could be a number of reasons for the change of name ............ perhaps Emily (the mother) had LOVEKIN as her maiden name and didn't marry John SMITH? Had she been married before? Did John SMITH have an alias?
It would be a good idea to catch them in the 1861 census if you can. Unfortunately, the 1860s are still not that well represented on freebmd. Baptisms of the children may shed more light on the scenario.
Best wishes
Casalguidi