Bias? What bias?

Following on from my post about BBC bias in its coverage of the #OurNHS march on 4th March, and my subsequent complaint to the BBC, I have now had a wholly unsatisfactory response from them...

Thank you for contacting us about our coverage of the NHS march in London on 4th March. We appreciate that you feel we didn’t give enough prominence to this story.
We covered this protest across BBC News platforms, including on BBC Radio bulletins, in the PM programme on Radio 4, in headlines and live coverage on the BBC News Channel, in our television bulletins on BBC One, and online.
http://www.bbc.co.uk/news/uk-39167350
Of course we appreciate that the NHS, and the challenges it faces, is a major news story, and one which many in our audience care about. At weekends, some of our news bulletins are shorter than during the week – but we would also point to our in-depth coverage of the NHS including a recent series of extended reports to explore this topic last month, during our “NHS Healthcheck” series.

We understand that you may still be unhappy with our coverage of this protest, but hope the above explains that we did report the protests across a range of News output. BBC News will continue to cover any significant developments relating to the NHS.
Thanks again for contacting us.

Kind Regards
BBC Complaints Team
www.bbc.co.uk/complaints
NB This is sent from an outgoing account only which is not monitored. You cannot reply to this email address but if necessary please contact us via our webform quoting any case number we provided.

That they consider their previous month's coverage of the NHS during their NHS Healthcheck series an adequate explanation for their poor ongoing coverage just beggars belief.   I remain unconvinced of their lack of bias, and I certainly heard very little about the march on Saturday on Radio 4 whilst it was happening or later the same evening after it had finished.

In their response the BBC also indicated their coverage online, via the link given, which did not appear in the list of top news stories and for which I had to go hunting (as I pointed out in my complaint). This was posted under the very misleading headline "NHS protest: Tens of thousands march against 'hospital cuts'" whereas the police were quoting in excess of 200,000 people, so by diminishing the turnout by a factor of ten the BBC appeared to be attempting to reduce the apparent impact of, and the participation in, the march in support of #OurNHS. Doing so is manipulation of the facts and should be denounced.

So the question is, can I take my complaint further or is the complaints processed closed?