Could not find a Radio Spares Cap, So this unit has 2 replaced caps we replaced a GEC KT 66 with a Groove Tubes KT66 HP and got it to bias quite fine. This is the head that you have to have it is a JTM 45 in the Rare Top Mount Chassis. Also The Output Transformer is 784-213 it is British and Old but might not be original. I would think that it would have been a RS.  This amp is sound and is very rare model. And A Tone Monster. BB