Just checked St Catherine's House Death Index (1984-2005) for the name 'Rose Catt' and came up with a couple of possibilities.
There were two in Surrey, one in Berkshire, one in Warwickshire and one in Northamptonshire.
But the three most likely candidates would be the following:-
Name: Elsie Rose Catt
Birth Date: 29 Apr 1913
Death Registration Month/Year: Oct 1993
Age at death (estimated): 80
Registration district: Hastings and Rother
Inferred County: East Sussex
Register number: B56A
Entry Number: 91
Name: Mabel Rose Catt
Birth Date: 7 Feb 1908
Death Registration Month/Year: Jun 1997
Age at death (estimated): 89
Registration district: Eastbourne
Inferred County: Sussex
Register number: B64E
Entry Number: 248
Name: Rose Annie Catt
Birth Date: 27 Feb 1895
Death Registration Month/Year: May 1994
Age at death (estimated): 99
Registration district: Eastbourne
Inferred County: Sussex
Register number: B55E
Entry Number: 273
Then there are the following Death Registrations of which one may be your 'Jim Catt':-
Name: Arthur James Catt
Birth Date: 26 Feb 1913
Death Registration Month/Year: Jun 1989
Age at death (estimated): 76
Registration district: Hastings and Rother
Inferred County: East Sussex
Volume: 18
Page: 704
Name: David James Catt
Birth Date: 15 Dec 1911
Death Registration Month/Year: Jan 1990
Age at death (estimated): 78
Registration district: Hastings and Rother
Inferred County: East Sussex
Volume: 18
Page: 755
Name: Ian James Catt
Birth Date: 4 Sep 1961
Death Registration Month/Year: Aug 1985
Age at death (estimated): 23
Registration district: Eastbourne
Inferred County: Sussex
Volume: 18
Page: 513
Name: Sidney James Catt
Birth Date: 16 Jun 1907
Death Registration Month/Year: Dec 1999
Age at death (estimated): 92
Registration district: Hastings and Rother
Inferred County: East Sussex
Register number: A69A
Entry Number: 39
Name: James Eric Catt
Birth Date: 5 Mar 1913
Death Registration Month/Year: Apr 1998
Age at death (estimated): 85
Registration district: Hastings and Rother
Inferred County: East Sussex
Register number: C64A
Entry Number: 86
Name: James George Catt
Birth Date: 20 May 1931
Death Registration Month/Year: Jan 1993
Age at death (estimated): 61
Registration district: Hastings and Rother
Inferred County: East Sussex
Register number: A48A
Entry Number: 260
These, based on the information you have supplied, seem the most likely entries.
Hope it helps - and if it looks promising let us know and we will try and track things a little further.