The pitch is awful but it's always been awful post Xmas, even before Wasps starting using it. That's just exacerbated the problem and like has been said pitch quality is far less important to them than us. If them playing on it is digging clumps out of it it's going to be hard to get it to regrow in these temperatures, even though it's been mild thus far.
The fact the pitch is slightly sunken might be a reason, creating a cold microclimate at pitch level. Under soil heating might protect the roots but it won't make the grass grow above soil so it probably needs the heat lamps on it. I also don't think the almost constant watering of it helps particularly - it makes the roots shallow and less hardy. Maybe it needs some tough love. I think the irrigation system should be under the soil too, making the roots dig in deeper for water making it stronger.
