* Graphic: Trade-weighted sterling since Brexit vote tmsnrt.rs/2hwV9Hv (Rewrites throughout, updates prices, adds further graphics) LONDON, April 23 (Reuters) - Sterling rebounded on Friday from a sharp fall on Thursday, on track for a second week of gains against the dollar after strong retail sales data and business surveys showed Britain’s economy might already be recovering from its worst annual contraction in 300 years. British retail sales rocketed last month as consumers prepared for a partial lifting of coronavirus lockdown restrictions, according to official data that also showed record peacetime government borrowing. Sales volumes leapt by 5.4% in March from February, the Office for National Statistics said. Economists polled by Reuters had expected an increase of 1.5%.