I visited the BA First lounge in T5 yesterday. I felt the buffet offerings and snack were inferior to the the previous caterers, but the table service was very good. Having spoken to a nice lady at BA Customer service in the lounge, it seems than many others share my view, and these views are being considered.
At least somebody is listening, which is a good sign.
I added a review of my flight which goes into more detail about my dining experience.
In fairness to all concerned, whilst there is a deterioration in the quality of the food on offer, I certainly couldn’t call it a disaster. More like teething problems.