Another possibility is Judy Garland:
http://www.helpmefind.com/plant/pl.php?n=3547
Check out the plant height - 4'10". Does that sound about like your
mother's rose? Rose size is another criterion you can use to narrow
your search.

Another possibility is Hiroshima's Children:
http://www.helpmefind.com/plant/pl.php?n=3284

Your photos kind of look like a floribunda - several blooms growing on
one stem - which is why I focussed on yellow blend Floribundas when I
searched in helpmefind. If that's true, it helps narrow down the very
wide field. If blooms tend to grow only one per stem it's more likely
a Hybrid Tea.

Don't be turned off by the first photo shown on a helpmefind page. If
there are other photos (and there often are), you can see the great
variety in photos and you might find one that looks like your
mother's.

Unfortunately there are very many roses that are bi- or multi-colored,
and the most common color combinations (on modern roses) are yellow
and redd or pink. Also, some roses are available in the UK, but not
in the USA, and vice versa. Both of the roses I linked above were
bred and introduced in the UK.

I'm assuming it's a modern rose, but on the off-hand chance it was
grown on its own roots (sometimes the case with modern shrubs), you
can always try taking several cuttings and grow your own copies. The
American Rose Society www.ars.org has articles on how to do that and
you don't have to be a member to access those articles. The general
technique should be the same on both sides of the Atlantic.

I don't want to ask an insulting question, but you did check for a
metal or plastic tag, right? Sometimes they can be very hard to find
but it's worth looking.

Anyway, good luck. Sometimes it's fairly easy to ID a rose from a
photo, but more often it's very hard because of so many roses in
existence.

Gail