York gran Sally Aston is usually to be seen in her pinny. But here she glams it up in the latest collections at M&S.

STYLE challenges don't come more challenging than Sally Aston. This 59-year-old grandmother is perfectly at home in her apron or in a smart navy skirt and blouse. "I don't have a pair of trousers," confesses Sally. "I've never even worn a pair."

As for high heels, she'd rather have a pair of flat, comfy shoes any day. "I'm always in a hurry, so I have to wear something I feel comfortable in," she says.

"I always have my apron on. I'm a caretaker at Dunnington school. My husband has an enormous allotment and I'm always jamming and pickling and don't have much occasion to get glammed up," adds Sally, who lives near the school.

Looking after her two granddaughters, Nicola, eight, and Emma, six, is another occupation.

"I pick them up from school and take them swimming and to netball matches and things like that," she says.

As the winner of the Evening Press competition to celebrate the arrival of the Per Una collection at Marks & Spencer, Sally's prize was a style makeover and £300 of vouchers to spend on a new look.

Per Una is the much-awaited range from fashion guru George Davies, pioneer of Next and the George at Asda label.

The emphasis is on affordable quality with a firm accent on fashion too. Fit is another important aspect of Per Una, with clothes cut for the true shapes of women today.

Per Una - which means 'for one woman' in Italian - is being hailed as suitable for the student to the grandmother, and Sally had the entire collection at her disposal when she arrived at Marks and Spencer's Parliament Street store in York for her re-style.

Our first hurdle was to coax Sally into some trousers.

"I don't think I'm the right shape for trousers," said Sally, who is five feet six and a size 14-16. "When I go on holiday abroad I don't even wear shorts - I prefer a skirt or a sun-dress."

But with a little persuasion, Sally was soon trying on some smart trouser suits and was even tempted into some suedette trousers worn under a long, woollen cardigan, for a smart and chic day-time look.

"It's very different," said Sally. "I can't say it's very comfortable, I feel the small of my back will get cold... I like to wear a full slip."

Sally was quite taken, however, with some brown leather ankle boots. "These are great - but I guess I could only wear them with trousers," she said.

Quite soon, the price pledge of Per Una was proving itself. We were knocked out by the camel cowl-neck sweater Sally wore under her cardi: it was a mix of angora, cashmere and silk and cost £22.

The next item to catch Sally's eye was a pretty deep-plum dress with a floral print. We teamed it with a deep pink cardigan, high heels and an aubergine handbag, for a great going-out look.

More heels were in order for the next outfit - a matching black top and skirt with sequins, which would be perfect for the festive season.

Sally was bracing herself for her family's reaction to her makeover day. "My granddaughters will think it's all a bit trendy for me - they've never seen me in anything like it," she said.

Husband Derek will be surprised too. "The last thing he said to me when he dropped me off was 'see if you can get some new aprons'."

Per Una, which arrived at Marks & Spencer's Parliament Street store on October 5, is already proving a hit - undoubted good news for the troubled firm which has seen profits dive for the past couple of years.

Ladieswear manager Claire Staton said: "It's a massive success and sales are doubling our estimates. And it's popular with all ages. We've had 16 year olds in and we had an 83-year-old lady buying a cardigan just the other day."

The collections will be changing every six weeks, with core pieces remaining throughout the season.

Claire added: "We're getting excellent feedback on the fit and a lot of customers are commenting on what good value the clothes are."

George Davies says his motto is "no compromise" and a close inspection of the tailoring, the fabric and the detail of Per Una suggests he is true to his words.

Sally was particularly impressed by this.

"There are some lovely details, like the sequins on the skirt and top and the fur cuffs on the long cardigan. It's little things like that that make it a bit different."