hello eveyone - thanks for the interest in the battery retainer. i should clarify a few things before i make any more :-
1. i haven't tested it in anger as i've not run the car yet (waiting for the shell from Jon Miller) so can't 100% guarantee it's race proven - i have no doubt it'll be up to it but i'd rather make that clear up front.
2. the retainer definately fits TP 4900's - i can't say about any other batteries as that's all i run. if you look on the TP website it gives the footprint of the other batteries which all look very similar but the heights are different. the retainer is 3mm thick which replicates the purple spacers under the battery strap post. a thinner battery may need some foam under the strap to stop it rattling.
3. the retainer will have a small (approx. 2mm diameter) hole at the end of the outside leg to glue it to the chassis. this stops any flexing of that leg. you will have to glue it to the chassis - the hole is there to drop a tiny amount of CA glue through whilst holding the leg in position - it is less messy than trying to spread glue on the retainer and then clamping it to the chassis
if, after all that
, you still are interested - let me know and i'll see what i can do to get some more made.