Nigel Wilson, a senior independent director at the car parts and bicycle retailer Halfords, has nearly doubled his stake in the firm, spending just less than £70,000 on shares.He took 20,000 at 349p a time and now has 41,000.Wilson, who is also chief financial officer at the business publisher United Business Media, joined Halfords in May 2004.Halfords has performed well given tough economic conditions over the past year.In July, the firm said sales in the quarter to end June increased by 3.1%, compared with this time last year, with like-for-like sales growth of 1.3%. Adjusting for the impact of Easter, sales increased by 1.9% representing like-for-like sales growth of 0.1%."This sales performance demonstrates an improving trajectory and was underpinned by strong multi channel growth, with Reserve and Collect revenues 55% higher than last year," Halfords said.Top Director BuysIdeal Shopping Direct (IDS) Director name: Mr Michael HancoxAmount purchased: 500,000 @ 80.00p Value: £400,000Halfords Group (HFD) Director name: Mr Nigel WilsonAmount purchased: 20,000 @ 349.00p Value: £69,800Melorio (MLO) Director name: Mr Hugh AldousAmount purchased: 50,000 @ 137.50p Value: £68,750Ideal Shopping Direct (IDS) Director name: Mr Ian JebsonAmount purchased: 40,000 @ 80.00p Value: £32,000Treatt (TET) Director name: Mr James GraceAmount purchased: 9,410 @ 280.00p Value: £26,348Alpha Strategic (APS) Director name: Mr Colin BarrowAmount purchased: 15,000 @ 105.00p Value: £15,750Top Director SellsGoodwin Plc (GDWN) Director name: Mr Matthew Stanley GoodwinAmount sold: 15,000 @ 1,133.00p Value: £169,950Southern Bear (STBR) Director name: Mr Steven Robert HancockAmount sold: 3,000,000 @ 2.10p Value: £63,000Oxford Instruments (OXIG) Director name: Mr Jonathan FlintAmount sold: 20,367 @ 188.10p Value: £38,310Oxford Instruments (OXIG) Director name: Mr Charles HolroydAmount sold: 6,605 @ 188.10p Value: £12,424