Weed for ID please

Weed for ID please

Observation - Weed for ID please - UK and Ireland. Description: These (currently) low-growing plants are likely to be cleared soon. If possible, I'd like a positive ID to help identify the cause of some distinctive red blisters covered with tiny yellow spots that appear on the undersides of some of the leaves.

These (currently) low-growing plants are likely to be cleared soon. If possible, I'd like a positive ID to help identify the cause of some distinctive red blisters covered with tiny yellow spots that appear on the undersides of some of the leaves.