Q1 What were your first impressions of the uniform? Please think about the fit, quality and cost of the items you bought when you answer.
We were really looking for gymslip type dresses and were not terribly impressed with the extra bits (little heart shaped zip pulls etc). That is to say DD was overjoyed and I was not. The reason being I think they are a bit tacky. It's just a personal preference but I prefer school uniforms to be plain because some schools IME do not like the fripperies.
Was also a bit put off by the ruched centre t shirts for small girls. They REALLY don't need to draw attention to their norks. 
Fit for trousers in DS was awful. Waist was fine, trousers were eight inches too long. A few inches, fair dos, but he's on the 50th percentile so not exactly freakishly short. Girls dresses much better fit. In fact had to go down in the sizes to get them to fit her rather than buy for age.
Quality is variable, the fabric on the trousers is not great, the dresses, despite looking thin, seem to have coped very well with DD falling off various things while wearing them and did not even tear when she fell off the top of the slide and grazed her knee underneath (remarkable!)
The tights though, umm well they are interesting. DD looked like Nora Batty in them and they did bunch round the ankles. She refused to wear them after the first day as they gave her 'elephant legs' I washed them in a hot wash and they shrank and now fit though. Now just have to keep them away from DH otherwise he'll do the same and they'll only fit Baby Annabelle.
Q2 How did you find the sizes? Did they fit well?
See above. Trousers not so much. DD wore her first trousers today and they fell down on the walk to school.
Her reception teacher showed me how to adjust them properly and she was fine. Her trousers were too long and needed turning up 4 inches.
I think the dresses are about right for length but I know from speaking to other mums in the school yard they thought the dresses were a bit long (they are just over knee length on DD) and they reckoned they'd get scuffed up when she kneeled down - time will tell. All the other little girls with M&S dresses had them on the knee or above so I think there is a difference in length at Matalan. DD has an M&S dress and it on her knee exactly.
Q3 What does your child think of their new uniform? Did they find it comfortable? Did they/you think what you had bought was fashionable/stylish (within the limits of school uniform!)?
DD likes the dresses very much. But she also likes the dresses we got from M&S and Sainburys and Tesco too.
See comments above about tights. DD liked the ruched top which she insisted I buy.
I still think it looks wrong. Their school is not very strict on uniforms (thank goodness) so they don't care about the dangly bits of details. But most of it is covered up with their emblemed jumpers/cardigans in any case.
Q4 Do you think that the items you bought are good value for money? If so, why? If not, why not?
Tights yes, tops yes, trousers, middling, dresses, no.
Comparing them to similar products from Sainsburys/Tesco. Particularly bearing in mind that the week I bought them both supermarkets had 20% off offers on uniforms.
Q5 And how did you find shopping for uniform in store?
To be frank it wasn't great. The Banbury store had a sign in the entrance with one mannequin with a school uniform on pointing vaguely to the left of the back of the store. We followed that direction but the uniforms were actually to the right of the back of the store 
The uniform displays were very crowded, there was no way you could get a buggy round. We did anyway but it was hard going and DS basically had his head in a pile of clothes at all times. The uniforms were right next to grabbable level toddler books
and we ended up with a tantrum due to this.
The uniform ranges were oddly laid out, sports wear flung in odd places and no sort of flow about it. The lighting in this store is also appalling making it very hard to get a good idea about colours for sweatshirts (luckily we were not looking for them but this is just general feedback). Also hard to see the difference between navy and black and grey etc. in that light.
There was very little left in smaller sizes and it seems 11-12 year olds have the choice of several hundred while a 4 year old is scraping around for anything. It was actually quite hard to spend £25 because of the lack of stock.
There were no staff in sight and I couldn't identify anywhere they could try things on.
The queue system was like the post office. You queue around a rope system and are called forward by announcement to the next available sales assistant.
I waited three minutes, there were two people serving and two people in front of us in the queue (so four people in total before us who were being dealt with). This was fine but putting rolls of wrapping paper by the queues is bad because the kids pretend they are jousting knights to pass the time unless subdued by food or threats of death. 
At the till there are toddler level sweets 
Sales Assistant had to go off to confer with colleagues about 'what to put the voucher through as' and they did go off into a little huddle. I think they thought I was a secret shopper or something. But she was cheery enough and offered me a Matalan card (which I took since I only have 25643 loyalty cards in my bag already
)
Shopping bag worked. Had a bought something heavier like a coat there is no way it would have lasted back to the car though. Was surprised to be sent home with hangers (which I didn't really need). Would have preferred to have been asked whether I wanted them and for them to be recycled.
In conclusion, Matalan is not somewhere I would have routinely expected to go for school uniforms. Didn't know they did them at all. But was pleasantly surprised by some things (the dresses, and the tights for comedy value), however the fit is not right for my kids.
But thanks for the voucher Matalan and anytime you need your Banbury store checking out again, get in touch :)