From gov.wales regarding Swansea lockdown:

”Can I carry out building or repair work in someone’s home?

Yes. Work carried out in people’s homes, for example by tradespeople, can continue. Our advice, however, is that both the tradesperson and household members should be well and have no symptoms of coronavirus. Please see the self-isolation guidance for more information. Like other businesses, tradespeople must take all reasonable measures to ensure that 2m distancing is maintained at all times when working in other people’s households and should follow the advice in our social distancing guidance. Please see the guidance on reasonable measures for more information.

We recommend no work should be carried out in any household which is isolating or where a person who is classed as extremely vulnerable unless it is to repair a fault which poses a direct risk to people’s safety – for example, emergency plumbing. In these cases, Public Health Wales can provide advice to tradespeople and households. But no work should be carried out by a tradesperson who has coronavirus symptoms, however mild.”

So provided you or I are free from symptoms, JPC should be able to visit your house still whilst observing social distancing, face masks, hand sanitizing etc