PUSB1987 wrote:
She wants some roses that are pink or red, have big flowers, nice strong
smell, easy to keep & are fairly resistant.

How many roses does she have space for? You can pay anything from 99p
in a 'cheap' shop (bargain shops, poundland or Wilkinsons) up to 15-20
quid in a nursery or garden centre for the specific one you want. IMHO
I would just pop out to whatever is cheapest near you and have a browse,
making sure to read the label.

Also after a bush/hedge, that is slow growing but grows to about 8ft.

Others will be able to help you better here, I'm no good with hedges.

Got about ?100 to spend for everything including some cheap flowers from
the garden center to add a bit of colour.

Are you after annuals to dot about and then redo next year, or something
to last? Probably a bit late for lilies and dahlia to go in, I guess.
Your mum might appreciate some aqualiga (columbine) plants, or throw some
seeds in next year - they seem quite hard to kill off (so make sure she
likes them first!) and they'll come back with little assistance year
after year.
I've just spotted i have some wallflowers that I left in, in lovely pale
pink and yellow, they're very pretty, but they've gone a bit straggley.
Hanging baskets with petunias and fucshias are my favourites.