On the day that Nahki Wells became the first Bradford City player to score in eight successive games, the club warned would-be buyers that their in-form striker was not for sale.Wells took his tally to six goals in five games on Saturday when he netted a goal in each half as Bradford beat Sheffield United 2-0 in the Yorkshire derby.With one week to go before the transfer window closes, Bradford’s assistant manager Steve Parkin insisted that the 23-year-old Bermudian was not available.“People have had more than 12 months to come and sign him and they’ve not bothered,” said Parkin. “We’re not going to sell him the week before the deadline.”Wells made history with his first goal came on the stroke of half-time and then with the match hanging in the balance he struck again in the 87th minute to seal the win in front of 18,000 fans at Valley Parade.Wells took a headed pass from Garry Thompson and scored with a low shot into the far corner to give the Bantams the lead. Strike partner James Hanson supplied the pass for Wells to score his second three minutes from the end and give Bradford their first win over their local rivals in 25 years.Parkin praised City’s momentum for carrying them through to their second League One victory, saying: “We were always aware it was going to be a terrific atmosphere. The place was bouncing before kick-off.“This is exactly what we want. This is what we’ve worked our socks off for over the last two years.“They’ve got some good players and we saw glimpses of that. But we have momentum and spirit and real good characters in the dressing room.”Added Parkin: “Both chairmen let us put a squad together to get promoted last season and hopefully we can get promoted this season. You don’t sell your best players if you want success. It is a no-go area.“It is terrific when you have a goalscorer like Nahki in the team, but he has a long way to go and it is important that he keeps his feet on the ground and keeps learning from the manager and the staff.”Wells, looking to match last season’s 26 goals, took his tally to six goals for the season in scoring for the eighth straight match going back to the end of last season when he netted in the last three games to help the club get promoted through the play-offs.Wells ended his most successful season in English football by becoming the first Bermudian to score at Wembley when he scored in the 3-0 win over Northampton in the play-off final.Wells has now eclipsed the previous record held by David Layne and John McCole who each scored in seven consecutive games. Layne achieved that feat at the end of the 1962 season while McCole managed a similar scoring streak three years earlier.Bradford are sixth in the standings, five points behind join leaders Leyton Orient and Peterborough. They are away to Stevenage on Saturday.