So you are not alone in this error and I too hold up my hands. Owning two modern diesels and too many old petrol cars, one with centre throttle, some with 3 some with 4 speed boxes, ordinary H pattern and reverse H, moving from one to the other is really helpful in causing confusion.
Anyway to your point, I have I confess managed diesel in petrol and the other way as well. Diesel in petrol, up to half a 12 gallon tank was no problem, the other way about can be since petrol is not good for the seals in injection pumps. I would not worry at all, the previous suggestions are good, however I would not wait until I needed to refil, but top up with petrol more frequently to dilute the remains diesel.
Good luck with the eye op.

Location: Autumnal Cotswolds

Hi Ian

I'll be very happy to do so after the edition is published. Nothing earth-shattering, but a salutory lesson nonetheless.

Location: North Herts

I said I would post more info after the publication of the latest edition of the 750MC Bulletin.

This is an extract, which will give you the relevant info on what to to watch out for. It is an account by a member of a local car club.

“On my way to the drive out day on Sunday I stopped at the BP garage to refuel. I pulled up at the first pump island and saw there were two pumps. The left pump said Regular unleaded, the right pump said Ultimate, both had green hoses. I always put the expensive fuel in the TR as I think it has a higher octane number and a reduced ethanol percentage.

I glanced to my right and the next pump island had two hoses which were black. Reassured I then topped up with Ultimate from a green hose.

On arrival at The Three Moorhens (about a mile) the engine would not tick over but otherwise ran OK. However when I restarted for the route the engine ran very roughly with CLOUDS of blue smoke. Realising what the problem might be I checked the refuelling receipt and saw what I had done.

What a Dumbo!!

Needless to say it was a stressful day and I was not flavour of the month with the Memsahib!

Three and a half hours later Fuel Assist arrived and did an excellent job of sucking all the contaminated fuel out of the TR and it started on the first turn of the key.

I have e-mailed BP to ask them to label their pumps more clearly but surprise, surprise, no response so far. A check on my local Shell garage shows all pumps having black hoses so the fuel companies seem to have different rules. If this prevents any club member from making the same mistake then it will have served its purpose.

My final comment is you MUST check what the fuel is from looking at what it says on the pump nozzle.”

Location: North Herts

Thank you all for your help and advice. I am currently out of action for doing anything on my seven as my catract operation has gone not to plan and I have difficulty in seeing anything clearly. When things get better I hope to make an attachment that will make the petrol filler neck smaller diameter to prevent the deisel filler going in. Such as modern petrol engine cars have.

John Mason

Location: Nottinghamshire