married: assessment separate or together?

I get married next month, and was wondering about taxation for when you are married. Can we choose whether to be assessed separately or together, or do the revenue make that decision for us?? My fiance is in a full time permanent position, but I work on a part time contract basis, usually from September to June. A friend told me that because I work this way, we would be better off not declaring we are married, and continuing to be assessed separately. ..
Over 12 months, my fiance is the higher earner.
Any advice would be welcome

There are many existing threads on this already.

[broken link removed]. In the year of marriage you remain assessed separately and balance things out at the end of the year. Then you can elect what married taxation approach you want. In general, and particularly if one of you is on 41% and the other is on 20%, then you may be better off and at worst will be no different if you opt for joint/aggregated married taxation and split the allowances/credits whatever way suits your. As ever getting a P21 balancing statement at the end of the year helps to deal with any discrepancies that might arise throughout the year for various reasons.