Not ever noticed any black specks in water, Shandy. Have been on a combi-boiler for the past 18 years, so do not think it can be anything to do with that.
I wanted (not needed) some work done in the flat, two new internal doors - one of them to be made a slider, plus some small work around the base of my kitchen units.
As I always like to use local people for such work, telephoned one and he came round same day. Nice young man, but I was rather taken aback at his quotation which was almost double what I was expecting. Even more so, as it seemed he would just do the actual work. I would have to arange and order the new items (doors, hinges, handles, etc. etc.), also pay for all old doors etc to be taken away. Not what I was looking for!!
So, yesterday got another firm to come in -totally different, firstly he came up with some ideas to me, they do everything, make the order, bring it with them, do the work, even the final coat of paint to doors, fit them and take everything away. Be interesting to see their quote. My gut feeling is that it will be closer to what I expected.
Not sure if this other man was looking at my nice flat, in one of the most expensive blocks in the town, and my grey hair and trying to take advantage!!!