Africa-focused oil and gas group Tower Resources said that drilling at its part-owned Welwitschia-1 well offshore Namibia is to start later than anticipated.The company said that its wholly-owned subsidiary Neptune Petroleum, which owns a 30% working interest in Welstischia, expects operator Repsol Exploration to start drilling operations in Walvis Bay on April 25th. "This is a little later than expected owing to prolonged acceptance-testing by Repsol in advance of it taking the drillship on a three-year contract," the company said.Drilling is expected to take up to 46 days.Tower's Chief Executive Graeme Thomson said he is "very excited" that the high-potential Welwitschia well will soon be drilled.The share price was 6.9% lower at 4.17p by 14:29 on Tuesday.BC