A retired MoneySaver has helped four of her neighbours who were on the wrong council tax band each get a £5,000 rebate from the council and lower their bills forever.

Up to 400,000 homes in England and Scotland are thought to be in the wrong council tax band – they could have been in the wrong band since 1991 when the original house valuations were done. (See our Council Tax Rebanding guide to see if you are paying too much and how to fight it.)

But getting your band changed can be as easy as contacting your local council, as Marjorie Cannadine, 63, discovered when she first moved into her former home in Lewes, East Sussex, 21 years ago.

She discovered a neighbour was in a lower band, took her case to her local council and had her band lowered in line with the neighbour's.

Marjorie says: "I lived in a four-bed townhouse along with five other houses in the road, exactly the same. When I moved in 21 years ago I checked the banding and one of the houses was lower than ours. I contacted Lewes District Council and it lowered our house one band down; the same as the other house."

But it wasn't until recently, when she was moving from the property to Horsham in West Sussex and checking the bandings for her new home, that she took another look at the house bandings on the road of the property she was moving out of and realised that the other four townhouses in Lewes were still on the higher banding.

She says: "I emailed my neighbour to let them know there could be a refund due to them and encouraged them to write to the council. They then passed the information on to the other next door neighbours. All four houses received a refund, including one couple out of the blue.

"They didn't write but the refund of £5,000 came through the post, so the council must have looked at the six townhouses and altered theirs to be the same.

"I have happy neighbours and I received a lovely bunch of flowers from one of them. I thought this was so exciting. I love getting Martin's Money Tips and just thought that this really was a great story."

Check your council tax band

Even though it is now 2014, it is the 1991 value that counts towards setting your band.If you are found to be paying too much, you will not only be making a saving by paying less each month, you can also get a rebate on the extra you've paid going back as a far as 1993, which could be thousands of pounds.

Helen Saxon, senior money writer at MoneySavingExpert.com, says: "Households should take inspiration from Marjorie's success story and check if they too can lower their council tax band and get backdated payments.

"Many households are in the wrong band because in 1991, when house valuations for council tax were undertaken, many councils rushed this process, leading to discrepancies.

"However, before appealing, be aware there is a risk it could push your band up, so challenging your band is not something to do speculatively without carrying out checks first."

Read our Council Tax Rebanding guide for full help.