That's the first positive reading in ten months for the UK retail sales balance. However, the expected retail sales for April is seen at -25 as compared to -15 in March. That shows that retailers are expecting the decline in sales to resume next month. CBI notes that:
"The stabilisation of retail sales in March should give some hope that the sector's downturn is bottoming out. The earlier timing of Easter will likely mean weaker year-on-year sales in April, but easing inflation should support retail spending going forward."