In article , Huge
writes
Does anyone know if it is permitted to take bikes on the Thameslink
service offpeak between Kings Cross Thameslink and London Bridge?

There are stairs/escalators to get to the street at both stations. Will
your kids be able to carry their bikes up/down them?

There's just a long ramp down from the platforms at London Bridge. No
stairs if you exit the main station entrance (into the bus station).

Access at KX-TL is a nightmare, though. Assuming the OP is arriving at
KX mainline by WAGN, it's a long walk on narrow pavements and very busy
roads, congested station entrance, then two flights of stairs down to
the platform (no lift or escalator).
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