Her birth registration date:

Surname First name(s) Mother District Vol  Page
Births Jun 1924   (>99%)
Welford Catherine Mellon W Derby 8b 675
________________

She was born too late for any marriage to have appeared in FreeBMD which currently only goes to 1940 or so.  But, (Feb 2013) this marriage is now on FreeBMD:

Surname First name(s) Spouse District Vol  Page
Marriages Jun 1950   (>99%)
Welford Catherine Sloan Crosby 10c 213
Sloan Merrick Welford Crosby 10c 213

And if that marriage was hers, then these Sloan children with a mother’s maiden name of Welford and born in Crosby might be hers too:

Surname First name(s) Mother District Vol  Page
Births Jun 1951   (>99%)
SLOAN Timothy P Welford Crosby 10c 104
Births Jun 1954   (>99%)
Sloan Paul R Welford Crosby 10c 129   
Births Dec 1955   (87%)
SLOAN Martin WELFORD Crosby 10c 113   
Births Mar 1957   (>99%)
SLOAN Kevin WELFORD Crosby 10c 123   
Births Mar 1960   (>99%)
SLOAN Jeremy WELFORD Wirral 10a 1059
_______________

There is this death at Guisborough which could have been her but the location does not make sense:

Surname First name(s) Age District Vol  Page
Deaths Dec 1926   (>99%)
Welford Catherine 1 Guisbro' 9d 598
________________

In 2018, no marriage found.  Nor any death with her birth name.  Nor any entry in 1939 Register.
_________________