By Suban Abdulla LONDON (Reuters) – Average asking prices for British homes made the strongest start to the year since 2020, according to a Rightmove survey on Monday that added to signs that the slowdown in the sector could be easing as demand picked up in January. The average price of homes put on sale between Dec. 3 and Jan. 6 was 1.3% higher than the month before, the biggest December to January rise since 2020 and more than double the average increase for this time of year, Rightmove said. House prices in Britain typically pick up at the start of January after a lull in the run-up to Chri…