Balancing Microbore Question

[mustbeunique]

My system is Gloworm fuelsaver, open vented, twin pipe microbore. I can see part of the pipework - 22mm flow and return feeding 8 mm microbore to 9 rads with TRVs. There is a tenth rad in bathroom directly above the boiler fed by 15mm with wheel valve and lockshield.
I have assumed this rad has no TRV because it provides a flow if all TRVs are shut. Should I balance this rad using the LS valve or leave it fully open?

 

[ScottishGasMan]

It should still be balanced with the rest of the radiators if your doing them, especially if it's the only one in 15mm as that will be the easiest route for water to take and will "steal" the flow from the microbore if it's not done