Indeed, both taps are in the open position, however, in place of a flexible filling 'loop' there is on your boiler a permanent fixed filling adaptor which has its own valve (the one nearest to the front) and is currently in the off position. Give it a quarter of a turn to fill to desired pressure then ensure it is turned off when complete.
Fabulous, MrTherm that did the trick and we now have hot water again.
One more question - the reason the pressure dropped we assume is because we were bleeding one of the upstairs radiators. There was no air in the rad but it does not warm up, all the others rads in the house are hot. Any suggestions as to why this one is cold?
Many thanks
Are the pipes feeding the cold rad, hot warm or cold? - has the cold rad worked recently?
Physically check both rad valves are open and operating (check the valve head pin is not stuck down if a TRV) if all seems o.k trace the run of those two pipes to where hot water is felt - report back if unsure.